Bibliography

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Early observations1, 2 indicated that the Earth\textquoterights Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies3, 4 showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep \textquoteleftslot\textquoteright region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary5, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location6. Recent observations have revealed unexpected radiation belt morphology7, 8, especially at ultrarelativistic kinetic energies9, 10 (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data11 reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth\textquoterights intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave\textendashparticle pitch angle scattering deep inside the Earth\textquoterights plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

Baker, D.; Jaynes, A.; Hoxie, V.; Thorne, R.; Foster, J.; Li, X.; Fennell, J.; Wygant, J.; Kanekal, S.; Erickson, P.; Kurth, W.; Li, W.; Ma, Q.; Schiller, Q.; Blum, L.; Malaspina, D.; Gerrard, A.; Lanzerotti, L.;

Published by: Nature      Published on: 11/2014

YEAR: 2014     DOI: 10.1038/nature13956

Magnetospheric physics; ultrarelativistic electrons; Van Allen Belts; Van Allen Probes

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Early observations1, 2 indicated that the Earth\textquoterights Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies3, 4 showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep \textquoteleftslot\textquoteright region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary5, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location6. Recent observations have revealed unexpected radiation belt morphology7, 8, especially at ultrarelativistic kinetic energies9, 10 (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data11 reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth\textquoterights intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave\textendashparticle pitch angle scattering deep inside the Earth\textquoterights plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

Baker, D.; Jaynes, A.; Hoxie, V.; Thorne, R.; Foster, J.; Li, X.; Fennell, J.; Wygant, J.; Kanekal, S.; Erickson, P.; Kurth, W.; Li, W.; Ma, Q.; Schiller, Q.; Blum, L.; Malaspina, D.; Gerrard, A.; Lanzerotti, L.;

Published by: Nature      Published on: 11/2014

YEAR: 2014     DOI: 10.1038/nature13956

Magnetospheric physics; ultrarelativistic electrons; Van Allen Belts; Van Allen Probes

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Early observations1, 2 indicated that the Earth\textquoterights Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies3, 4 showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep \textquoteleftslot\textquoteright region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary5, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location6. Recent observations have revealed unexpected radiation belt morphology7, 8, especially at ultrarelativistic kinetic energies9, 10 (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data11 reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth\textquoterights intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave\textendashparticle pitch angle scattering deep inside the Earth\textquoterights plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

Baker, D.; Jaynes, A.; Hoxie, V.; Thorne, R.; Foster, J.; Li, X.; Fennell, J.; Wygant, J.; Kanekal, S.; Erickson, P.; Kurth, W.; Li, W.; Ma, Q.; Schiller, Q.; Blum, L.; Malaspina, D.; Gerrard, A.; Lanzerotti, L.;

Published by: Nature      Published on: 11/2014

YEAR: 2014     DOI: 10.1038/nature13956

Magnetospheric physics; ultrarelativistic electrons; Van Allen Belts; Van Allen Probes

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Early observations1, 2 indicated that the Earth\textquoterights Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies3, 4 showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep \textquoteleftslot\textquoteright region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary5, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location6. Recent observations have revealed unexpected radiation belt morphology7, 8, especially at ultrarelativistic kinetic energies9, 10 (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data11 reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth\textquoterights intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave\textendashparticle pitch angle scattering deep inside the Earth\textquoterights plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

Baker, D.; Jaynes, A.; Hoxie, V.; Thorne, R.; Foster, J.; Li, X.; Fennell, J.; Wygant, J.; Kanekal, S.; Erickson, P.; Kurth, W.; Li, W.; Ma, Q.; Schiller, Q.; Blum, L.; Malaspina, D.; Gerrard, A.; Lanzerotti, L.;

Published by: Nature      Published on: 11/2014

YEAR: 2014     DOI: 10.1038/nature13956

Magnetospheric physics; ultrarelativistic electrons; Van Allen Belts; Van Allen Probes

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Early observations1, 2 indicated that the Earth\textquoterights Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies3, 4 showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep \textquoteleftslot\textquoteright region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary5, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location6. Recent observations have revealed unexpected radiation belt morphology7, 8, especially at ultrarelativistic kinetic energies9, 10 (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data11 reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth\textquoterights intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave\textendashparticle pitch angle scattering deep inside the Earth\textquoterights plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

Baker, D.; Jaynes, A.; Hoxie, V.; Thorne, R.; Foster, J.; Li, X.; Fennell, J.; Wygant, J.; Kanekal, S.; Erickson, P.; Kurth, W.; Li, W.; Ma, Q.; Schiller, Q.; Blum, L.; Malaspina, D.; Gerrard, A.; Lanzerotti, L.;

Published by: Nature      Published on: 11/2014

YEAR: 2014     DOI: 10.1038/nature13956

Magnetospheric physics; ultrarelativistic electrons; Van Allen Belts; Van Allen Probes

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Early observations1, 2 indicated that the Earth\textquoterights Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies3, 4 showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep \textquoteleftslot\textquoteright region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary5, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location6. Recent observations have revealed unexpected radiation belt morphology7, 8, especially at ultrarelativistic kinetic energies9, 10 (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data11 reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth\textquoterights intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave\textendashparticle pitch angle scattering deep inside the Earth\textquoterights plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

Baker, D.; Jaynes, A.; Hoxie, V.; Thorne, R.; Foster, J.; Li, X.; Fennell, J.; Wygant, J.; Kanekal, S.; Erickson, P.; Kurth, W.; Li, W.; Ma, Q.; Schiller, Q.; Blum, L.; Malaspina, D.; Gerrard, A.; Lanzerotti, L.;

Published by: Nature      Published on: 11/2014

YEAR: 2014     DOI: 10.1038/nature13956

Magnetospheric physics; ultrarelativistic electrons; Van Allen Belts; Van Allen Probes

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Early observations1, 2 indicated that the Earth\textquoterights Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies3, 4 showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep \textquoteleftslot\textquoteright region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary5, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location6. Recent observations have revealed unexpected radiation belt morphology7, 8, especially at ultrarelativistic kinetic energies9, 10 (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data11 reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth\textquoterights intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave\textendashparticle pitch angle scattering deep inside the Earth\textquoterights plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

Baker, D.; Jaynes, A.; Hoxie, V.; Thorne, R.; Foster, J.; Li, X.; Fennell, J.; Wygant, J.; Kanekal, S.; Erickson, P.; Kurth, W.; Li, W.; Ma, Q.; Schiller, Q.; Blum, L.; Malaspina, D.; Gerrard, A.; Lanzerotti, L.;

Published by: Nature      Published on: 11/2014

YEAR: 2014     DOI: 10.1038/nature13956

Magnetospheric physics; ultrarelativistic electrons; Van Allen Belts; Van Allen Probes

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Early observations1, 2 indicated that the Earth\textquoterights Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies3, 4 showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep \textquoteleftslot\textquoteright region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary5, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location6. Recent observations have revealed unexpected radiation belt morphology7, 8, especially at ultrarelativistic kinetic energies9, 10 (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data11 reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth\textquoterights intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave\textendashparticle pitch angle scattering deep inside the Earth\textquoterights plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

Baker, D.; Jaynes, A.; Hoxie, V.; Thorne, R.; Foster, J.; Li, X.; Fennell, J.; Wygant, J.; Kanekal, S.; Erickson, P.; Kurth, W.; Li, W.; Ma, Q.; Schiller, Q.; Blum, L.; Malaspina, D.; Gerrard, A.; Lanzerotti, L.;

Published by: Nature      Published on: 11/2014

YEAR: 2014     DOI: 10.1038/nature13956

Magnetospheric physics; ultrarelativistic electrons; Van Allen Belts; Van Allen Probes

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Early observations1, 2 indicated that the Earth\textquoterights Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies3, 4 showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep \textquoteleftslot\textquoteright region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary5, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location6. Recent observations have revealed unexpected radiation belt morphology7, 8, especially at ultrarelativistic kinetic energies9, 10 (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data11 reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth\textquoterights intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave\textendashparticle pitch angle scattering deep inside the Earth\textquoterights plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

Baker, D.; Jaynes, A.; Hoxie, V.; Thorne, R.; Foster, J.; Li, X.; Fennell, J.; Wygant, J.; Kanekal, S.; Erickson, P.; Kurth, W.; Li, W.; Ma, Q.; Schiller, Q.; Blum, L.; Malaspina, D.; Gerrard, A.; Lanzerotti, L.;

Published by: Nature      Published on: 11/2014

YEAR: 2014     DOI: 10.1038/nature13956

Magnetospheric physics; ultrarelativistic electrons; Van Allen Belts; Van Allen Probes

An impenetrable barrier to ultrarelativistic electrons in the Van Allen radiation belts

Early observations1, 2 indicated that the Earth\textquoterights Van Allen radiation belts could be separated into an inner zone dominated by high-energy protons and an outer zone dominated by high-energy electrons. Subsequent studies3, 4 showed that electrons of moderate energy (less than about one megaelectronvolt) often populate both zones, with a deep \textquoteleftslot\textquoteright region largely devoid of particles between them. There is a region of dense cold plasma around the Earth known as the plasmasphere, the outer boundary of which is called the plasmapause. The two-belt radiation structure was explained as arising from strong electron interactions with plasmaspheric hiss just inside the plasmapause boundary5, with the inner edge of the outer radiation zone corresponding to the minimum plasmapause location6. Recent observations have revealed unexpected radiation belt morphology7, 8, especially at ultrarelativistic kinetic energies9, 10 (more than five megaelectronvolts). Here we analyse an extended data set that reveals an exceedingly sharp inner boundary for the ultrarelativistic electrons. Additional, concurrently measured data11 reveal that this barrier to inward electron radial transport does not arise because of a physical boundary within the Earth\textquoterights intrinsic magnetic field, and that inward radial diffusion is unlikely to be inhibited by scattering by electromagnetic transmitter wave fields. Rather, we suggest that exceptionally slow natural inward radial diffusion combined with weak, but persistent, wave\textendashparticle pitch angle scattering deep inside the Earth\textquoterights plasmasphere can combine to create an almost impenetrable barrier through which the most energetic Van Allen belt electrons cannot migrate.

Baker, D.; Jaynes, A.; Hoxie, V.; Thorne, R.; Foster, J.; Li, X.; Fennell, J.; Wygant, J.; Kanekal, S.; Erickson, P.; Kurth, W.; Li, W.; Ma, Q.; Schiller, Q.; Blum, L.; Malaspina, D.; Gerrard, A.; Lanzerotti, L.;

Published by: Nature      Published on: 11/2014

YEAR: 2014     DOI: 10.1038/nature13956

Magnetospheric physics; ultrarelativistic electrons; Van Allen Belts; Van Allen Probes

Initial Measurements of O-ion and He-ion Decay Rates Observed from the Van Allen Probes RBSPICE Instrument

H-ion (~45-keV to ~600-keV), He-ion (~65-keV to ~520-keV), and O-ion (~140-keV to ~1130-keV) integral flux measurements, from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft B, are reported. These abundance data form a cohesive picture of ring current ions during the first nine months of measurements. Furthermore, the data presented herein are used to show injection characteristics via the He-ion/H-ion abundance ratio and the O-ion/H-ion abundance ratio. Of unique interest to ring current dynamics are the spatial-temporal decay characteristics of the two injected populations. We observe that He-ions decay more quickly at lower L-shells, on the orderof ~0.8-day at L-shells of 3\textendash4, and decay more slowly with higher L-shell, on the order of ~1.7-days at L-shells of 5\textendash6. Conversely, O-ions decay very rapidly (~1.5-hours) across all L-shells. The He-ion decay time are consistent with previously measured and calculated lifetimes associated with charge exchange. The O-ion decay time is much faster than predicted and is attributed to the inclusion of higher energy (>500-keV) O-ions in our decay rate estimation. We note that these measurements demonstrate a compelling need for calculation of high energy O-ion loss rates, which have not been adequately studied in the literature to date.

Gerrard, Andrew; Lanzerotti, Louis; Gkioulidou, Matina; Mitchell, Donald; Manweiler, Jerry; Bortnik, Jacob; Keika, Kunihiro;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020374

inner magnetosphere; ion decay rates; Spacecraft measurements; Van Allen Probes

Initial Measurements of O-ion and He-ion Decay Rates Observed from the Van Allen Probes RBSPICE Instrument

H-ion (~45-keV to ~600-keV), He-ion (~65-keV to ~520-keV), and O-ion (~140-keV to ~1130-keV) integral flux measurements, from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft B, are reported. These abundance data form a cohesive picture of ring current ions during the first nine months of measurements. Furthermore, the data presented herein are used to show injection characteristics via the He-ion/H-ion abundance ratio and the O-ion/H-ion abundance ratio. Of unique interest to ring current dynamics are the spatial-temporal decay characteristics of the two injected populations. We observe that He-ions decay more quickly at lower L-shells, on the orderof ~0.8-day at L-shells of 3\textendash4, and decay more slowly with higher L-shell, on the order of ~1.7-days at L-shells of 5\textendash6. Conversely, O-ions decay very rapidly (~1.5-hours) across all L-shells. The He-ion decay time are consistent with previously measured and calculated lifetimes associated with charge exchange. The O-ion decay time is much faster than predicted and is attributed to the inclusion of higher energy (>500-keV) O-ions in our decay rate estimation. We note that these measurements demonstrate a compelling need for calculation of high energy O-ion loss rates, which have not been adequately studied in the literature to date.

Gerrard, Andrew; Lanzerotti, Louis; Gkioulidou, Matina; Mitchell, Donald; Manweiler, Jerry; Bortnik, Jacob; Keika, Kunihiro;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020374

inner magnetosphere; ion decay rates; Spacecraft measurements; Van Allen Probes

Initial Measurements of O-ion and He-ion Decay Rates Observed from the Van Allen Probes RBSPICE Instrument

H-ion (~45-keV to ~600-keV), He-ion (~65-keV to ~520-keV), and O-ion (~140-keV to ~1130-keV) integral flux measurements, from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft B, are reported. These abundance data form a cohesive picture of ring current ions during the first nine months of measurements. Furthermore, the data presented herein are used to show injection characteristics via the He-ion/H-ion abundance ratio and the O-ion/H-ion abundance ratio. Of unique interest to ring current dynamics are the spatial-temporal decay characteristics of the two injected populations. We observe that He-ions decay more quickly at lower L-shells, on the orderof ~0.8-day at L-shells of 3\textendash4, and decay more slowly with higher L-shell, on the order of ~1.7-days at L-shells of 5\textendash6. Conversely, O-ions decay very rapidly (~1.5-hours) across all L-shells. The He-ion decay time are consistent with previously measured and calculated lifetimes associated with charge exchange. The O-ion decay time is much faster than predicted and is attributed to the inclusion of higher energy (>500-keV) O-ions in our decay rate estimation. We note that these measurements demonstrate a compelling need for calculation of high energy O-ion loss rates, which have not been adequately studied in the literature to date.

Gerrard, Andrew; Lanzerotti, Louis; Gkioulidou, Matina; Mitchell, Donald; Manweiler, Jerry; Bortnik, Jacob; Keika, Kunihiro;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020374

inner magnetosphere; ion decay rates; Spacecraft measurements; Van Allen Probes

Initial Measurements of O-ion and He-ion Decay Rates Observed from the Van Allen Probes RBSPICE Instrument

H-ion (~45-keV to ~600-keV), He-ion (~65-keV to ~520-keV), and O-ion (~140-keV to ~1130-keV) integral flux measurements, from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft B, are reported. These abundance data form a cohesive picture of ring current ions during the first nine months of measurements. Furthermore, the data presented herein are used to show injection characteristics via the He-ion/H-ion abundance ratio and the O-ion/H-ion abundance ratio. Of unique interest to ring current dynamics are the spatial-temporal decay characteristics of the two injected populations. We observe that He-ions decay more quickly at lower L-shells, on the orderof ~0.8-day at L-shells of 3\textendash4, and decay more slowly with higher L-shell, on the order of ~1.7-days at L-shells of 5\textendash6. Conversely, O-ions decay very rapidly (~1.5-hours) across all L-shells. The He-ion decay time are consistent with previously measured and calculated lifetimes associated with charge exchange. The O-ion decay time is much faster than predicted and is attributed to the inclusion of higher energy (>500-keV) O-ions in our decay rate estimation. We note that these measurements demonstrate a compelling need for calculation of high energy O-ion loss rates, which have not been adequately studied in the literature to date.

Gerrard, Andrew; Lanzerotti, Louis; Gkioulidou, Matina; Mitchell, Donald; Manweiler, Jerry; Bortnik, Jacob; Keika, Kunihiro;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020374

inner magnetosphere; ion decay rates; Spacecraft measurements; Van Allen Probes

Initial Measurements of O-ion and He-ion Decay Rates Observed from the Van Allen Probes RBSPICE Instrument

H-ion (~45-keV to ~600-keV), He-ion (~65-keV to ~520-keV), and O-ion (~140-keV to ~1130-keV) integral flux measurements, from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft B, are reported. These abundance data form a cohesive picture of ring current ions during the first nine months of measurements. Furthermore, the data presented herein are used to show injection characteristics via the He-ion/H-ion abundance ratio and the O-ion/H-ion abundance ratio. Of unique interest to ring current dynamics are the spatial-temporal decay characteristics of the two injected populations. We observe that He-ions decay more quickly at lower L-shells, on the orderof ~0.8-day at L-shells of 3\textendash4, and decay more slowly with higher L-shell, on the order of ~1.7-days at L-shells of 5\textendash6. Conversely, O-ions decay very rapidly (~1.5-hours) across all L-shells. The He-ion decay time are consistent with previously measured and calculated lifetimes associated with charge exchange. The O-ion decay time is much faster than predicted and is attributed to the inclusion of higher energy (>500-keV) O-ions in our decay rate estimation. We note that these measurements demonstrate a compelling need for calculation of high energy O-ion loss rates, which have not been adequately studied in the literature to date.

Gerrard, Andrew; Lanzerotti, Louis; Gkioulidou, Matina; Mitchell, Donald; Manweiler, Jerry; Bortnik, Jacob; Keika, Kunihiro;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020374

inner magnetosphere; ion decay rates; Spacecraft measurements; Van Allen Probes

On long decays of electrons in the vicinity of the slot region observed by HEO3

Long decay periods of electron counts, which follow abrupt rises and last from weeks to months, have been observed by the HEO3 spacecraft in the vicinity of the slot region between the years 1998 and 2007. During the most stable decay periods as selected, e-folding timescales are extracted and statistically analyzed from observations as a function of L-shell and electron energy. A challenge is to reproduce the observed timescales from simulations of pitch angle diffusion by three acting waves\textendashthe plasmaspheric hiss, lightning-generated whistlers, and VLF transmitter waves. We perform full numerical simulations to accurately compute electron lifetimes. We choose to use the method and wave parameters proposed by Abel \& Thorne [1998] with the goal to assess whether they can reproduce lifetimes extracted from HEO observations. We show how hiss dominantly affect high energy electrons (E > 2 MeV) for L in [2, 3.5] and VLF transmitter waves control residency times of low energy electrons (<0.4 MeV) around L = 2. These interactions induce characteristic shapes of the lifetime profiles that will be discussed. We show how the wave amplitudes can be adjusted for the particular energy particles that are dominantly affected by one wave type only. Using these amplitudes, mean HEO lifetimes are reproduced within a factor 2 to 5. VLF occurrence rates and hiss amplitude turn out significantly higher than those proposed by Abel \& Thorne [1998]. The wide energy response of the sensors complicates the analysis because it blurs the electron lifetime dependence on energy, increases the overall lifetimes and reduces the differences between the different channel lifetimes. In particular, our simulations suggest the flux measured by an integrated energy sensor aboard HEO has a variable slope, i.e. a variable lifetime, during 10-20 days in our data, due to the faster decay of the low residency time particles while slower decaying particles control the steady decay. It can explain some of the multi-slopes decays observed by HEO. HEO electron long decay timescales are also compared to the timescales previously observed from SAMPEX and CRRES with differences attributed to factors such as instrument characteristic and different satellite orbits.

Ripoll, J.-F.; Chen, Y.; Fennell, J.; Friedel, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020449

electron; HEO; Slot region

On long decays of electrons in the vicinity of the slot region observed by HEO3

Long decay periods of electron counts, which follow abrupt rises and last from weeks to months, have been observed by the HEO3 spacecraft in the vicinity of the slot region between the years 1998 and 2007. During the most stable decay periods as selected, e-folding timescales are extracted and statistically analyzed from observations as a function of L-shell and electron energy. A challenge is to reproduce the observed timescales from simulations of pitch angle diffusion by three acting waves\textendashthe plasmaspheric hiss, lightning-generated whistlers, and VLF transmitter waves. We perform full numerical simulations to accurately compute electron lifetimes. We choose to use the method and wave parameters proposed by Abel \& Thorne [1998] with the goal to assess whether they can reproduce lifetimes extracted from HEO observations. We show how hiss dominantly affect high energy electrons (E > 2 MeV) for L in [2, 3.5] and VLF transmitter waves control residency times of low energy electrons (<0.4 MeV) around L = 2. These interactions induce characteristic shapes of the lifetime profiles that will be discussed. We show how the wave amplitudes can be adjusted for the particular energy particles that are dominantly affected by one wave type only. Using these amplitudes, mean HEO lifetimes are reproduced within a factor 2 to 5. VLF occurrence rates and hiss amplitude turn out significantly higher than those proposed by Abel \& Thorne [1998]. The wide energy response of the sensors complicates the analysis because it blurs the electron lifetime dependence on energy, increases the overall lifetimes and reduces the differences between the different channel lifetimes. In particular, our simulations suggest the flux measured by an integrated energy sensor aboard HEO has a variable slope, i.e. a variable lifetime, during 10-20 days in our data, due to the faster decay of the low residency time particles while slower decaying particles control the steady decay. It can explain some of the multi-slopes decays observed by HEO. HEO electron long decay timescales are also compared to the timescales previously observed from SAMPEX and CRRES with differences attributed to factors such as instrument characteristic and different satellite orbits.

Ripoll, J.-F.; Chen, Y.; Fennell, J.; Friedel, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020449

electron; HEO; Slot region

On long decays of electrons in the vicinity of the slot region observed by HEO3

Long decay periods of electron counts, which follow abrupt rises and last from weeks to months, have been observed by the HEO3 spacecraft in the vicinity of the slot region between the years 1998 and 2007. During the most stable decay periods as selected, e-folding timescales are extracted and statistically analyzed from observations as a function of L-shell and electron energy. A challenge is to reproduce the observed timescales from simulations of pitch angle diffusion by three acting waves\textendashthe plasmaspheric hiss, lightning-generated whistlers, and VLF transmitter waves. We perform full numerical simulations to accurately compute electron lifetimes. We choose to use the method and wave parameters proposed by Abel \& Thorne [1998] with the goal to assess whether they can reproduce lifetimes extracted from HEO observations. We show how hiss dominantly affect high energy electrons (E > 2 MeV) for L in [2, 3.5] and VLF transmitter waves control residency times of low energy electrons (<0.4 MeV) around L = 2. These interactions induce characteristic shapes of the lifetime profiles that will be discussed. We show how the wave amplitudes can be adjusted for the particular energy particles that are dominantly affected by one wave type only. Using these amplitudes, mean HEO lifetimes are reproduced within a factor 2 to 5. VLF occurrence rates and hiss amplitude turn out significantly higher than those proposed by Abel \& Thorne [1998]. The wide energy response of the sensors complicates the analysis because it blurs the electron lifetime dependence on energy, increases the overall lifetimes and reduces the differences between the different channel lifetimes. In particular, our simulations suggest the flux measured by an integrated energy sensor aboard HEO has a variable slope, i.e. a variable lifetime, during 10-20 days in our data, due to the faster decay of the low residency time particles while slower decaying particles control the steady decay. It can explain some of the multi-slopes decays observed by HEO. HEO electron long decay timescales are also compared to the timescales previously observed from SAMPEX and CRRES with differences attributed to factors such as instrument characteristic and different satellite orbits.

Ripoll, J.-F.; Chen, Y.; Fennell, J.; Friedel, R.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020449

electron; HEO; Slot region

Meeting Report: Solar Energetic Particle Measurements Intercalibration Workshop, 11 April 2014, Boulder, Colorado

Following the conclusion of the 2014 Space Weather Week in Boulder, Colorado, the NOAA National Geophysical Data Center and Space Weather Prediction Center cohosted a 1 day workshop on the intercalibration of solar energetic particle (SEP) measurements. The overall purpose of this workshop was to discuss the intercalibration of SEP measurements from different instruments and different spacecraft, to foster new cooperative intercalibration efforts, and to identify a path forward for establishing a set of intercalibration guidelines. The detailed objectives of this workshop were described by Rodriguez and Onsager [2014]. Ten talks were given at the workshop (available at ftp://ftp.ngdc.noaa.gov/STP/publications/spe_intercal/), interspersed with extensive discussions. One outcome of these discussions is a recommendation that a set of guidelines be drafted for the on-orbit cross comparison of solar energetic particle measurements, similar to the first optical calibration guidelines developed for the Global Space-based Inter-Calibration System (GSICS) of the World Meteorological Organization (WMO) and the Coordination Group for Meteorological Satellites [Datla et al., 2009].

Rodriguez, Juan; Onsager, Terrance; Heynderickx, Daniel; Jiggens, Piers;

Published by: Space Weather      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/swe.v12.1110.1002/2014SW001134

cross calibration; interoperability; Solar Energetic Particles

Meeting Report: Solar Energetic Particle Measurements Intercalibration Workshop, 11 April 2014, Boulder, Colorado

Following the conclusion of the 2014 Space Weather Week in Boulder, Colorado, the NOAA National Geophysical Data Center and Space Weather Prediction Center cohosted a 1 day workshop on the intercalibration of solar energetic particle (SEP) measurements. The overall purpose of this workshop was to discuss the intercalibration of SEP measurements from different instruments and different spacecraft, to foster new cooperative intercalibration efforts, and to identify a path forward for establishing a set of intercalibration guidelines. The detailed objectives of this workshop were described by Rodriguez and Onsager [2014]. Ten talks were given at the workshop (available at ftp://ftp.ngdc.noaa.gov/STP/publications/spe_intercal/), interspersed with extensive discussions. One outcome of these discussions is a recommendation that a set of guidelines be drafted for the on-orbit cross comparison of solar energetic particle measurements, similar to the first optical calibration guidelines developed for the Global Space-based Inter-Calibration System (GSICS) of the World Meteorological Organization (WMO) and the Coordination Group for Meteorological Satellites [Datla et al., 2009].

Rodriguez, Juan; Onsager, Terrance; Heynderickx, Daniel; Jiggens, Piers;

Published by: Space Weather      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/swe.v12.1110.1002/2014SW001134

cross calibration; interoperability; Solar Energetic Particles

Meeting Report: Solar Energetic Particle Measurements Intercalibration Workshop, 11 April 2014, Boulder, Colorado

Following the conclusion of the 2014 Space Weather Week in Boulder, Colorado, the NOAA National Geophysical Data Center and Space Weather Prediction Center cohosted a 1 day workshop on the intercalibration of solar energetic particle (SEP) measurements. The overall purpose of this workshop was to discuss the intercalibration of SEP measurements from different instruments and different spacecraft, to foster new cooperative intercalibration efforts, and to identify a path forward for establishing a set of intercalibration guidelines. The detailed objectives of this workshop were described by Rodriguez and Onsager [2014]. Ten talks were given at the workshop (available at ftp://ftp.ngdc.noaa.gov/STP/publications/spe_intercal/), interspersed with extensive discussions. One outcome of these discussions is a recommendation that a set of guidelines be drafted for the on-orbit cross comparison of solar energetic particle measurements, similar to the first optical calibration guidelines developed for the Global Space-based Inter-Calibration System (GSICS) of the World Meteorological Organization (WMO) and the Coordination Group for Meteorological Satellites [Datla et al., 2009].

Rodriguez, Juan; Onsager, Terrance; Heynderickx, Daniel; Jiggens, Piers;

Published by: Space Weather      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/swe.v12.1110.1002/2014SW001134

cross calibration; interoperability; Solar Energetic Particles

Meeting Report: Solar Energetic Particle Measurements Intercalibration Workshop, 11 April 2014, Boulder, Colorado

Following the conclusion of the 2014 Space Weather Week in Boulder, Colorado, the NOAA National Geophysical Data Center and Space Weather Prediction Center cohosted a 1 day workshop on the intercalibration of solar energetic particle (SEP) measurements. The overall purpose of this workshop was to discuss the intercalibration of SEP measurements from different instruments and different spacecraft, to foster new cooperative intercalibration efforts, and to identify a path forward for establishing a set of intercalibration guidelines. The detailed objectives of this workshop were described by Rodriguez and Onsager [2014]. Ten talks were given at the workshop (available at ftp://ftp.ngdc.noaa.gov/STP/publications/spe_intercal/), interspersed with extensive discussions. One outcome of these discussions is a recommendation that a set of guidelines be drafted for the on-orbit cross comparison of solar energetic particle measurements, similar to the first optical calibration guidelines developed for the Global Space-based Inter-Calibration System (GSICS) of the World Meteorological Organization (WMO) and the Coordination Group for Meteorological Satellites [Datla et al., 2009].

Rodriguez, Juan; Onsager, Terrance; Heynderickx, Daniel; Jiggens, Piers;

Published by: Space Weather      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/swe.v12.1110.1002/2014SW001134

cross calibration; interoperability; Solar Energetic Particles

Modeling radiation belt electron acceleration by ULF fast mode waves, launched by solar wind dynamic pressure fluctuations

We investigate the magnetospheric MHD and energetic electron response to a Storm Sudden Commencement (SSC) and subsequent magnetopause buffeting, focusing on an interval following an SSC event on 25 November 2001. We find that the electron flux signatures observed by LANL, Cluster, and GOES spacecraft during this event can largely be reproduced using an advective kinetic model for electron phase space density, using externally prescribed electromagnetic field inputs, (herein described as a \textquotedbllefttest-kinetic model\textquotedblright) with electromagnetic field inputs provided by a 2-D linear ideal MHD model for ULF waves. In particular, we find modulations in electron flux phase shifted by 90\textdegree from the local azimuthal ULF wave electric field (Eφ) and a net enhancement in electron flux after 1.5 h for energies between 500 keV and 1.5 MeV near geosynchronous orbit. We also demonstrate that electrons in this energy range satisfy the drift resonance condition for the ULF waves produced by the MHD model. This confirms the conclusions reached by Tan et al. (2011), that the energization process in this case is dominated by drift-resonant interactions between electrons and MHD fast mode waves, produced by fluctuations in solar wind dynamic pressure.

Degeling, A.; Rankin, R.; Zong, Q.-G.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2013JA019672

adiabatic electron transport; magnetopause buffeting; Radiation belts; ULF waves

Observations and modeling of EMIC wave properties in the presence of multiple ion species as function of magnetic local time

Electromagnetic ion cyclotron (EMIC) wave generation and propagation in Earth\textquoterights magnetosphere depend on readily measurable hot (a few to tens of keV) plasma sheet ions, elusive plasmaspheric or ionospheric cold (sub-eV to a few eV) ions, and partially heated warm ions (tens to hundreds of eV). Previous work has assumed all low-energy ions are cold and not considered possible effects of warm ions. Using measurements by multiple Time History of Events and Macroscale Interactions during Substorms spacecraft, we analyze four typical EMIC wave events in the four magnetic local time sectors and consider the properties of both cold and warm ions supplied from previous statistical studies to interpret the wave observations using linear theory. As expected, we find that dusk EMIC waves grow due to the presence of drifting hot anisotropic protons and cold plasmaspheric ions with a dominant cold proton component. Near midnight, EMIC waves are less common because warm heavy ions that suppress wave growth are more abundant there. The waves can grow when cold, plume-like density enhancements are present, however. Dawn EMIC waves, known for their peculiar properties, are generated away from the equator and change polarization during propagation through the warm plasma cloak. Noon EMIC waves can also be generated nonlocally and their properties modified during propagation by a plasmaspheric plume combined with low-energy ions from solar and terrestrial sources. Accounting for multiple ion species, measured wave dispersion, and propagation characteristics can explain previously elusive EMIC wave properties and are therefore important for future studies of EMIC wave effects on energetic particle depletion.

Lee, Justin; Angelopoulos, Vassilis;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020469

EMIC waves; ion composition; ion cyclotron waves; low-energy ions; THEMIS; warm plasma effects

Observations and modeling of EMIC wave properties in the presence of multiple ion species as function of magnetic local time

Electromagnetic ion cyclotron (EMIC) wave generation and propagation in Earth\textquoterights magnetosphere depend on readily measurable hot (a few to tens of keV) plasma sheet ions, elusive plasmaspheric or ionospheric cold (sub-eV to a few eV) ions, and partially heated warm ions (tens to hundreds of eV). Previous work has assumed all low-energy ions are cold and not considered possible effects of warm ions. Using measurements by multiple Time History of Events and Macroscale Interactions during Substorms spacecraft, we analyze four typical EMIC wave events in the four magnetic local time sectors and consider the properties of both cold and warm ions supplied from previous statistical studies to interpret the wave observations using linear theory. As expected, we find that dusk EMIC waves grow due to the presence of drifting hot anisotropic protons and cold plasmaspheric ions with a dominant cold proton component. Near midnight, EMIC waves are less common because warm heavy ions that suppress wave growth are more abundant there. The waves can grow when cold, plume-like density enhancements are present, however. Dawn EMIC waves, known for their peculiar properties, are generated away from the equator and change polarization during propagation through the warm plasma cloak. Noon EMIC waves can also be generated nonlocally and their properties modified during propagation by a plasmaspheric plume combined with low-energy ions from solar and terrestrial sources. Accounting for multiple ion species, measured wave dispersion, and propagation characteristics can explain previously elusive EMIC wave properties and are therefore important for future studies of EMIC wave effects on energetic particle depletion.

Lee, Justin; Angelopoulos, Vassilis;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020469

EMIC waves; ion composition; ion cyclotron waves; low-energy ions; THEMIS; warm plasma effects

Radial diffusion simulations of the 20 September 2007 radiation belt dropout

This is a study of a dropout of radiation belt electrons, associated with an isolated solar wind density pulse on 20 September 2007, as seen by the solid-state telescopes (SST) detectors on THEMIS (Time History of Events and Macroscale Interactions during Substorms). Omnidirectional fluxes were converted to phase space density at constant invariants M = 700 MeV G-1 and K = 0.014 RE G1/2, with the assumption of local pitch angle α ≈ 80\textdegree and using the T04 magnetic field model. The last closed drift shell, which was calculated throughout the time interval, never came within the simulation outer boundary of L* = 6. It is found, using several different models for diffusion rates, that radial diffusion alone only allows the data-driven, time-dependent boundary values at Lmax = 6 and Lmin = 3.7 to propagate a few tenths of an RE during the simulation; far too slow to account for the dropout observed over the broad range of L* = 4\textendash5.5. Pitch angle diffusion via resonant interactions with several types of waves (chorus, electromagnetic ion cyclotron waves, and plasmaspheric and plume hiss) also seems problematic, for several reasons which are discussed.

Albert, J.;

Published by: Annales Geophysicae      Published on: 11/2014

YEAR: 2014     DOI: 10.5194/angeo-32-925-2014

radial diffusion

Statistical results describing the bandwidth and coherence coefficient of whistler mode waves using THEMIS waveform data

The bandwidths and coherence coefficients of lower band whistler mode waves are analyzed using Time History of Events and Macroscale Interactions during Substorms (THEMIS) waveform data for rising tones, falling tones, and hiss-like emissions separately. We also evaluate their dependences on the spatial location, electron density, the ratio of plasma frequency to local electron gyrofrequency (fpe/fce), and the wave amplitude. Our results show that the bandwidth normalized by the local electron gyrofrequency (fce) of rising and falling tones is very narrow (~0.01 fce), smaller than that of the hiss-like emissions (~0.025 fce). Meanwhile, the normalized bandwidth of discrete emissions gradually decreases with increasing wave amplitude, whereas that of hiss-like emissions increases slowly. The coherence coefficient of rising and falling tones is extremely large (~1), while the coherence coefficient of hiss-like emissions is smaller but is still larger than 0.5. For all categories of whistler mode waves, the normalized bandwidth increases at larger L shells. Furthermore, the normalized bandwidth is positively correlated with local fpe/fce but is inversely correlated with the electron density. Interactions between radiation belt electrons and whistler mode waves have been widely described by quasi-linear diffusion theory. Our results suggest that although quasi-linear theory is not entirely applicable for modeling electron interactions with rising and falling tones due to their narrow bandwidth and high coherence coefficient, it is suitable to treat wave-particle interactions between electrons and low-amplitude hiss-like emissions. Moreover, the correlations between the normalized bandwidth of chorus waves (especially the discrete emissions) and other parameters may provide insights for the generation mechanism of chorus waves.

Gao, X.; Li, W.; Thorne, R.; Bortnik, J.; Angelopoulos, V.; Lu, Q.; Tao, X.; Wang, S.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020158

bandwidth; coherence coefficient; nonlinear; quasi-linear; THEMIS; whistler mode waves

Statistical results describing the bandwidth and coherence coefficient of whistler mode waves using THEMIS waveform data

The bandwidths and coherence coefficients of lower band whistler mode waves are analyzed using Time History of Events and Macroscale Interactions during Substorms (THEMIS) waveform data for rising tones, falling tones, and hiss-like emissions separately. We also evaluate their dependences on the spatial location, electron density, the ratio of plasma frequency to local electron gyrofrequency (fpe/fce), and the wave amplitude. Our results show that the bandwidth normalized by the local electron gyrofrequency (fce) of rising and falling tones is very narrow (~0.01 fce), smaller than that of the hiss-like emissions (~0.025 fce). Meanwhile, the normalized bandwidth of discrete emissions gradually decreases with increasing wave amplitude, whereas that of hiss-like emissions increases slowly. The coherence coefficient of rising and falling tones is extremely large (~1), while the coherence coefficient of hiss-like emissions is smaller but is still larger than 0.5. For all categories of whistler mode waves, the normalized bandwidth increases at larger L shells. Furthermore, the normalized bandwidth is positively correlated with local fpe/fce but is inversely correlated with the electron density. Interactions between radiation belt electrons and whistler mode waves have been widely described by quasi-linear diffusion theory. Our results suggest that although quasi-linear theory is not entirely applicable for modeling electron interactions with rising and falling tones due to their narrow bandwidth and high coherence coefficient, it is suitable to treat wave-particle interactions between electrons and low-amplitude hiss-like emissions. Moreover, the correlations between the normalized bandwidth of chorus waves (especially the discrete emissions) and other parameters may provide insights for the generation mechanism of chorus waves.

Gao, X.; Li, W.; Thorne, R.; Bortnik, J.; Angelopoulos, V.; Lu, Q.; Tao, X.; Wang, S.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 11/2014

YEAR: 2014     DOI: 10.1002/2014JA020158

bandwidth; coherence coefficient; nonlinear; quasi-linear; THEMIS; whistler mode waves

A ULF wave driver of ring current energization

ULF wave radial diffusion plays an important role in the transport of energetic electrons in the outer radiation belt, yet similar ring current transport is seldom considered even though ions satisfy a nearly identical drift resonance condition albeit without the relativistic correction. By examining the correlation between ULF wave power and the response of the ring current, characterized by Dst, we demonstrate a definite correlation between ULF wave power and Dst. Significantly, the lagged correlation peaks such that ULF waves precede the response of the ring current and Dst. We suggest that this correlation is the result of enhanced radial transport and energization of ring current ions through drift resonance and ULF wave radial diffusion of ring current ions. An analysis and comparison of the ion and electron diffusion coefficients further support this conclusion, ULF waves providing an important missing physical transport process explaining Dst underestimation in ring current models.

Murphy, Kyle; Mann, Ian; Ozeke, Louis;

Published by: Geophysical Research Letters      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/grl.v41.1910.1002/2014GL061253

Dst; radial diffusion; ring current dynamics; ULF waves; wave particle interactions

An unusual long-lived relativistic electron enhancement event excited by sequential CMEs

An unusual long-lived intense relativistic electron enhancement event from July to August 2004 is examined using data from Fengyun-1, POES, GOES, ACE, the Cluster Mission and geomagnetic indices. During the initial 6 days of this event, the observed fluxes in the outer zone enhanced continuously and their maximum increased from 2.1 \texttimes 102 cm-2\textperiodcenteredsr-1\textperiodcentereds-1 to 3.5 \texttimes 104 cm-2\textperiodcenteredsr-1\textperiodcentereds-1, the region of enhanced fluxes extended from L = 3.5-6.5 to L = 2.5-6.5, and the flux peak location shifted inward from L ~ 4.2 to L ~ 3.3. During the following 7 days, without any locational movement, the flux peak increased slowly and exceeded the pre-storm fluxes by about 4 orders of magnitude. Subsequently, the decay rate of relativistic electrons is so slow that the peak remains over 104 cm-2\textperiodcenteredsr-1\textperiodcentereds-1 for about 30 days. The drift-resonance between ULF waves, which arose from high-speed solar wind and frequent impulses of solar wind dynamic pressure, and energetic electrons injected by substorms could be an important acceleration mechanism in this event. The local acceleration by whistler mode chorus could be another mechanism contributing to this enhancement. The plasmaspheric response to the interplanetary disturbances reveals that the enhanced outer zone is divided into two portions by the plasmapause. Accordingly, the slow loss rate in the plasmasphere due to hiss primarily contributed to the long-lived characteristic of this event. This event reveals that the outer zone population behaviors are dominated by the interplanetary variations together with the responses of geomagnetic field and plasmasphere to these variations.

Yang, Xiao; Zhu, Guang; Zhang, Xiao; Sun, Yue; Liang, Jin; Wei, Xin;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA019797

Geomagnetic storm/substorm; Interplanetary magnetic field; Plasmapause; Relativistic electron; Solar wind

Whistler Anisotropy Instabilities as the Source of Banded Chorus: Van Allen Probes Observations and Particle-in-Cell Simulations

Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell (PIC) simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from HOPE instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper-band chorus, and that the hot component drives the electromagnetic lower-band chorus; the gap at \~ Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.

Fu, Xiangrong; Cowee, Misa; Friedel, Reinhard; Funsten, Herbert; Gary, Peter; Hospodarsky, George; Kletzing, Craig; Kurth, William; Larsen, Brian; Liu, Kaijun; MacDonald, Elizabeth; Min, Kyungguk; Reeves, Geoffrey; Skoug, Ruth; Winske, Dan;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020364

Chorus; HOPE; particle-in-cell simulation; Van Allen Probes

Whistler Anisotropy Instabilities as the Source of Banded Chorus: Van Allen Probes Observations and Particle-in-Cell Simulations

Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell (PIC) simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from HOPE instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper-band chorus, and that the hot component drives the electromagnetic lower-band chorus; the gap at \~ Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.

Fu, Xiangrong; Cowee, Misa; Friedel, Reinhard; Funsten, Herbert; Gary, Peter; Hospodarsky, George; Kletzing, Craig; Kurth, William; Larsen, Brian; Liu, Kaijun; MacDonald, Elizabeth; Min, Kyungguk; Reeves, Geoffrey; Skoug, Ruth; Winske, Dan;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020364

Chorus; HOPE; particle-in-cell simulation; Van Allen Probes

Whistler Anisotropy Instabilities as the Source of Banded Chorus: Van Allen Probes Observations and Particle-in-Cell Simulations

Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell (PIC) simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from HOPE instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper-band chorus, and that the hot component drives the electromagnetic lower-band chorus; the gap at \~ Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.

Fu, Xiangrong; Cowee, Misa; Friedel, Reinhard; Funsten, Herbert; Gary, Peter; Hospodarsky, George; Kletzing, Craig; Kurth, William; Larsen, Brian; Liu, Kaijun; MacDonald, Elizabeth; Min, Kyungguk; Reeves, Geoffrey; Skoug, Ruth; Winske, Dan;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020364

Chorus; HOPE; particle-in-cell simulation; Van Allen Probes

Whistler Anisotropy Instabilities as the Source of Banded Chorus: Van Allen Probes Observations and Particle-in-Cell Simulations

Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell (PIC) simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from HOPE instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper-band chorus, and that the hot component drives the electromagnetic lower-band chorus; the gap at \~ Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.

Fu, Xiangrong; Cowee, Misa; Friedel, Reinhard; Funsten, Herbert; Gary, Peter; Hospodarsky, George; Kletzing, Craig; Kurth, William; Larsen, Brian; Liu, Kaijun; MacDonald, Elizabeth; Min, Kyungguk; Reeves, Geoffrey; Skoug, Ruth; Winske, Dan;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020364

Chorus; HOPE; particle-in-cell simulation; Van Allen Probes

Whistler Anisotropy Instabilities as the Source of Banded Chorus: Van Allen Probes Observations and Particle-in-Cell Simulations

Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell (PIC) simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from HOPE instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper-band chorus, and that the hot component drives the electromagnetic lower-band chorus; the gap at \~ Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.

Fu, Xiangrong; Cowee, Misa; Friedel, Reinhard; Funsten, Herbert; Gary, Peter; Hospodarsky, George; Kletzing, Craig; Kurth, William; Larsen, Brian; Liu, Kaijun; MacDonald, Elizabeth; Min, Kyungguk; Reeves, Geoffrey; Skoug, Ruth; Winske, Dan;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020364

Chorus; HOPE; particle-in-cell simulation; Van Allen Probes

Whistler Anisotropy Instabilities as the Source of Banded Chorus: Van Allen Probes Observations and Particle-in-Cell Simulations

Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell (PIC) simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from HOPE instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper-band chorus, and that the hot component drives the electromagnetic lower-band chorus; the gap at \~ Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.

Fu, Xiangrong; Cowee, Misa; Friedel, Reinhard; Funsten, Herbert; Gary, Peter; Hospodarsky, George; Kletzing, Craig; Kurth, William; Larsen, Brian; Liu, Kaijun; MacDonald, Elizabeth; Min, Kyungguk; Reeves, Geoffrey; Skoug, Ruth; Winske, Dan;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020364

Chorus; HOPE; particle-in-cell simulation; Van Allen Probes

Whistler Anisotropy Instabilities as the Source of Banded Chorus: Van Allen Probes Observations and Particle-in-Cell Simulations

Magnetospheric banded chorus is enhanced whistler waves with frequencies ωr < Ωe, where Ωe is the electron cyclotron frequency, and a characteristic spectral gap at ωr ≃ Ωe/2. This paper uses spacecraft observations and two-dimensional particle-in-cell (PIC) simulations in a magnetized, homogeneous, collisionless plasma to test the hypothesis that banded chorus is due to local linear growth of two branches of the whistler anisotropy instability excited by two distinct, anisotropic electron components of significantly different temperatures. The electron densities and temperatures are derived from HOPE instrument measurements on the Van Allen Probes A satellite during a banded chorus event on 1 November 2012. The observations are consistent with a three-component electron model consisting of a cold (a few tens of eV) population, a warm (a few hundred eV) anisotropic population, and a hot (a few keV) anisotropic population. The simulations use plasma and field parameters as measured from the satellite during this event except for two numbers: the anisotropies of the warm and the hot electron components are enhanced over the measured values in order to obtain relatively rapid instability growth. The simulations show that the warm component drives the quasi-electrostatic upper-band chorus, and that the hot component drives the electromagnetic lower-band chorus; the gap at \~ Ωe/2 is a natural consequence of the growth of two whistler modes with different properties.

Fu, Xiangrong; Cowee, Misa; Friedel, Reinhard; Funsten, Herbert; Gary, Peter; Hospodarsky, George; Kletzing, Craig; Kurth, William; Larsen, Brian; Liu, Kaijun; MacDonald, Elizabeth; Min, Kyungguk; Reeves, Geoffrey; Skoug, Ruth; Winske, Dan;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020364

Chorus; HOPE; particle-in-cell simulation; Van Allen Probes

The Evolving Space Weather System - Van Allen Probes Contribution

The overarching goal and purpose of the study of space weather is clear - to understand and address the issues caused by solar disturbances on humans and technological systems. Space weather has evolved in the past few decades from a collection of concerned agencies and researchers to a critical function of the National Weather Service of NOAA. The general effects have also evolved from the well-known telegraph disruptions of the mid-1800\textquoterights to modern day disturbances of the electric power grid, communications and navigation, human spaceflight and spacecraft systems. The last two items in this list, and specifically the effects of penetrating radiation, were the impetus for the space weather broadcast implemented on NASA\textquoterights Van Allen Probes\textquoteright twin pair of satellites, launched in August of 2012 and orbiting directly through Earth\textquoterights severe radiation belts. The Van Allen Probes mission, formerly the Radiation Belt Storm Probes (RBSP, http://vanallenprobes.jhuapl.edu), were renamed soon after launch to honor the discoverer of Earth\textquoterights radiation belts at the beginning of the space age, the late James Van Allen (the spacecraft themselves are still referred to as RBSP-A and RBSP-B). The Van Allen Probes (Mauk et al., 2012 and other team contributions in the same special issue of Space Science Reviews, 2012) are one part of NASA\textquoterights Living With a Star (LWS, http://lws.gsfc.nasa.gov) program formulated to advance the scientific understanding of the connection between solar disturbances, the resulting heliospheric conditions and their effects on the geospace and Earth environment.

Zanetti, L.; Mauk, B.; Fox, N.J.; Barnes, R.J.; Weiss, M.; Sotirelis, T.S.; Raouafi, N.-E.; Kessel, R.; Becker, H.;

Published by: Space Weather      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014SW001108

Radiation belts; Van Allen Probes

The Evolving Space Weather System - Van Allen Probes Contribution

The overarching goal and purpose of the study of space weather is clear - to understand and address the issues caused by solar disturbances on humans and technological systems. Space weather has evolved in the past few decades from a collection of concerned agencies and researchers to a critical function of the National Weather Service of NOAA. The general effects have also evolved from the well-known telegraph disruptions of the mid-1800\textquoterights to modern day disturbances of the electric power grid, communications and navigation, human spaceflight and spacecraft systems. The last two items in this list, and specifically the effects of penetrating radiation, were the impetus for the space weather broadcast implemented on NASA\textquoterights Van Allen Probes\textquoteright twin pair of satellites, launched in August of 2012 and orbiting directly through Earth\textquoterights severe radiation belts. The Van Allen Probes mission, formerly the Radiation Belt Storm Probes (RBSP, http://vanallenprobes.jhuapl.edu), were renamed soon after launch to honor the discoverer of Earth\textquoterights radiation belts at the beginning of the space age, the late James Van Allen (the spacecraft themselves are still referred to as RBSP-A and RBSP-B). The Van Allen Probes (Mauk et al., 2012 and other team contributions in the same special issue of Space Science Reviews, 2012) are one part of NASA\textquoterights Living With a Star (LWS, http://lws.gsfc.nasa.gov) program formulated to advance the scientific understanding of the connection between solar disturbances, the resulting heliospheric conditions and their effects on the geospace and Earth environment.

Zanetti, L.; Mauk, B.; Fox, N.J.; Barnes, R.J.; Weiss, M.; Sotirelis, T.S.; Raouafi, N.-E.; Kessel, R.; Becker, H.;

Published by: Space Weather      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014SW001108

Radiation belts; Van Allen Probes

The Evolving Space Weather System - Van Allen Probes Contribution

The overarching goal and purpose of the study of space weather is clear - to understand and address the issues caused by solar disturbances on humans and technological systems. Space weather has evolved in the past few decades from a collection of concerned agencies and researchers to a critical function of the National Weather Service of NOAA. The general effects have also evolved from the well-known telegraph disruptions of the mid-1800\textquoterights to modern day disturbances of the electric power grid, communications and navigation, human spaceflight and spacecraft systems. The last two items in this list, and specifically the effects of penetrating radiation, were the impetus for the space weather broadcast implemented on NASA\textquoterights Van Allen Probes\textquoteright twin pair of satellites, launched in August of 2012 and orbiting directly through Earth\textquoterights severe radiation belts. The Van Allen Probes mission, formerly the Radiation Belt Storm Probes (RBSP, http://vanallenprobes.jhuapl.edu), were renamed soon after launch to honor the discoverer of Earth\textquoterights radiation belts at the beginning of the space age, the late James Van Allen (the spacecraft themselves are still referred to as RBSP-A and RBSP-B). The Van Allen Probes (Mauk et al., 2012 and other team contributions in the same special issue of Space Science Reviews, 2012) are one part of NASA\textquoterights Living With a Star (LWS, http://lws.gsfc.nasa.gov) program formulated to advance the scientific understanding of the connection between solar disturbances, the resulting heliospheric conditions and their effects on the geospace and Earth environment.

Zanetti, L.; Mauk, B.; Fox, N.J.; Barnes, R.J.; Weiss, M.; Sotirelis, T.S.; Raouafi, N.-E.; Kessel, R.; Becker, H.;

Published by: Space Weather      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014SW001108

Radiation belts; Van Allen Probes

The Evolving Space Weather System - Van Allen Probes Contribution

The overarching goal and purpose of the study of space weather is clear - to understand and address the issues caused by solar disturbances on humans and technological systems. Space weather has evolved in the past few decades from a collection of concerned agencies and researchers to a critical function of the National Weather Service of NOAA. The general effects have also evolved from the well-known telegraph disruptions of the mid-1800\textquoterights to modern day disturbances of the electric power grid, communications and navigation, human spaceflight and spacecraft systems. The last two items in this list, and specifically the effects of penetrating radiation, were the impetus for the space weather broadcast implemented on NASA\textquoterights Van Allen Probes\textquoteright twin pair of satellites, launched in August of 2012 and orbiting directly through Earth\textquoterights severe radiation belts. The Van Allen Probes mission, formerly the Radiation Belt Storm Probes (RBSP, http://vanallenprobes.jhuapl.edu), were renamed soon after launch to honor the discoverer of Earth\textquoterights radiation belts at the beginning of the space age, the late James Van Allen (the spacecraft themselves are still referred to as RBSP-A and RBSP-B). The Van Allen Probes (Mauk et al., 2012 and other team contributions in the same special issue of Space Science Reviews, 2012) are one part of NASA\textquoterights Living With a Star (LWS, http://lws.gsfc.nasa.gov) program formulated to advance the scientific understanding of the connection between solar disturbances, the resulting heliospheric conditions and their effects on the geospace and Earth environment.

Zanetti, L.; Mauk, B.; Fox, N.J.; Barnes, R.J.; Weiss, M.; Sotirelis, T.S.; Raouafi, N.-E.; Kessel, R.; Becker, H.;

Published by: Space Weather      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014SW001108

Radiation belts; Van Allen Probes

The Evolving Space Weather System - Van Allen Probes Contribution

The overarching goal and purpose of the study of space weather is clear - to understand and address the issues caused by solar disturbances on humans and technological systems. Space weather has evolved in the past few decades from a collection of concerned agencies and researchers to a critical function of the National Weather Service of NOAA. The general effects have also evolved from the well-known telegraph disruptions of the mid-1800\textquoterights to modern day disturbances of the electric power grid, communications and navigation, human spaceflight and spacecraft systems. The last two items in this list, and specifically the effects of penetrating radiation, were the impetus for the space weather broadcast implemented on NASA\textquoterights Van Allen Probes\textquoteright twin pair of satellites, launched in August of 2012 and orbiting directly through Earth\textquoterights severe radiation belts. The Van Allen Probes mission, formerly the Radiation Belt Storm Probes (RBSP, http://vanallenprobes.jhuapl.edu), were renamed soon after launch to honor the discoverer of Earth\textquoterights radiation belts at the beginning of the space age, the late James Van Allen (the spacecraft themselves are still referred to as RBSP-A and RBSP-B). The Van Allen Probes (Mauk et al., 2012 and other team contributions in the same special issue of Space Science Reviews, 2012) are one part of NASA\textquoterights Living With a Star (LWS, http://lws.gsfc.nasa.gov) program formulated to advance the scientific understanding of the connection between solar disturbances, the resulting heliospheric conditions and their effects on the geospace and Earth environment.

Zanetti, L.; Mauk, B.; Fox, N.J.; Barnes, R.J.; Weiss, M.; Sotirelis, T.S.; Raouafi, N.-E.; Kessel, R.; Becker, H.;

Published by: Space Weather      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014SW001108

Radiation belts; Van Allen Probes

The Evolving Space Weather System - Van Allen Probes Contribution

The overarching goal and purpose of the study of space weather is clear - to understand and address the issues caused by solar disturbances on humans and technological systems. Space weather has evolved in the past few decades from a collection of concerned agencies and researchers to a critical function of the National Weather Service of NOAA. The general effects have also evolved from the well-known telegraph disruptions of the mid-1800\textquoterights to modern day disturbances of the electric power grid, communications and navigation, human spaceflight and spacecraft systems. The last two items in this list, and specifically the effects of penetrating radiation, were the impetus for the space weather broadcast implemented on NASA\textquoterights Van Allen Probes\textquoteright twin pair of satellites, launched in August of 2012 and orbiting directly through Earth\textquoterights severe radiation belts. The Van Allen Probes mission, formerly the Radiation Belt Storm Probes (RBSP, http://vanallenprobes.jhuapl.edu), were renamed soon after launch to honor the discoverer of Earth\textquoterights radiation belts at the beginning of the space age, the late James Van Allen (the spacecraft themselves are still referred to as RBSP-A and RBSP-B). The Van Allen Probes (Mauk et al., 2012 and other team contributions in the same special issue of Space Science Reviews, 2012) are one part of NASA\textquoterights Living With a Star (LWS, http://lws.gsfc.nasa.gov) program formulated to advance the scientific understanding of the connection between solar disturbances, the resulting heliospheric conditions and their effects on the geospace and Earth environment.

Zanetti, L.; Mauk, B.; Fox, N.J.; Barnes, R.J.; Weiss, M.; Sotirelis, T.S.; Raouafi, N.-E.; Kessel, R.; Becker, H.;

Published by: Space Weather      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014SW001108

Radiation belts; Van Allen Probes

Interactions of energetic electrons with ULF waves triggered by interplanetary shock: Van Allen Probes observations in the magnetotail

We present in situ observations of a shock-induced substorm-like event on 13 April 2013 observed by the newly launched Van Allen twin probes. Substorm-like electron injections with energy of 30\textendash500 keV were observed in the region from L\~5.2 to 5.5 immediately after the shock arrival (followed by energetic electron drift echoes). Meanwhile, the electron flux was clearly and strongly varying on the ULF wave time scale. It is found that both toroidal and poloidal mode ULF waves with a period of 150 s emerged following the magnetotail magnetic field reconfiguration after the interplanetary (IP) shock passage. The poloidal mode is more intense than the toroidal mode. The 90\textdegree phase shift between the poloidal mode Br and Ea suggests the standing poloidal waves in the Northern Hemisphere. Furthermore, the energetic electron flux modulations indicate that the azimuthal wave number is \~14. Direct evidence of drift resonance between the injected electrons and the excited poloidal ULF wave has been obtained. The resonant energy is estimated to be between 150 keV and 230 keV. Two possible scenaria on ULF wave triggering are discussed: vortex-like flow structure-driven field line resonance and ULF wave growth through drift resonance. It is found that the IP shock may trigger intense ULF wave and energetic electron behavior at L\~3 to 6 on the nightside, while the time profile of the wave is different from dayside cases.

Hao, Y.; Zong, Q.-G.; Wang, Y.; Zhou, X.-Z.; Zhang, Hui; Fu, S; Pu, Z; Spence, H.; Blake, J.; Bonnell, J.; Wygant, J.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020023

energetic particles; interplanetary shock; magnetotail ULF wave; poloidal and toroidal mode; Van Allen Probes; wave-particle interactions

Interactions of energetic electrons with ULF waves triggered by interplanetary shock: Van Allen Probes observations in the magnetotail

We present in situ observations of a shock-induced substorm-like event on 13 April 2013 observed by the newly launched Van Allen twin probes. Substorm-like electron injections with energy of 30\textendash500 keV were observed in the region from L\~5.2 to 5.5 immediately after the shock arrival (followed by energetic electron drift echoes). Meanwhile, the electron flux was clearly and strongly varying on the ULF wave time scale. It is found that both toroidal and poloidal mode ULF waves with a period of 150 s emerged following the magnetotail magnetic field reconfiguration after the interplanetary (IP) shock passage. The poloidal mode is more intense than the toroidal mode. The 90\textdegree phase shift between the poloidal mode Br and Ea suggests the standing poloidal waves in the Northern Hemisphere. Furthermore, the energetic electron flux modulations indicate that the azimuthal wave number is \~14. Direct evidence of drift resonance between the injected electrons and the excited poloidal ULF wave has been obtained. The resonant energy is estimated to be between 150 keV and 230 keV. Two possible scenaria on ULF wave triggering are discussed: vortex-like flow structure-driven field line resonance and ULF wave growth through drift resonance. It is found that the IP shock may trigger intense ULF wave and energetic electron behavior at L\~3 to 6 on the nightside, while the time profile of the wave is different from dayside cases.

Hao, Y.; Zong, Q.-G.; Wang, Y.; Zhou, X.-Z.; Zhang, Hui; Fu, S; Pu, Z; Spence, H.; Blake, J.; Bonnell, J.; Wygant, J.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020023

energetic particles; interplanetary shock; magnetotail ULF wave; poloidal and toroidal mode; Van Allen Probes; wave-particle interactions

Interactions of energetic electrons with ULF waves triggered by interplanetary shock: Van Allen Probes observations in the magnetotail

We present in situ observations of a shock-induced substorm-like event on 13 April 2013 observed by the newly launched Van Allen twin probes. Substorm-like electron injections with energy of 30\textendash500 keV were observed in the region from L\~5.2 to 5.5 immediately after the shock arrival (followed by energetic electron drift echoes). Meanwhile, the electron flux was clearly and strongly varying on the ULF wave time scale. It is found that both toroidal and poloidal mode ULF waves with a period of 150 s emerged following the magnetotail magnetic field reconfiguration after the interplanetary (IP) shock passage. The poloidal mode is more intense than the toroidal mode. The 90\textdegree phase shift between the poloidal mode Br and Ea suggests the standing poloidal waves in the Northern Hemisphere. Furthermore, the energetic electron flux modulations indicate that the azimuthal wave number is \~14. Direct evidence of drift resonance between the injected electrons and the excited poloidal ULF wave has been obtained. The resonant energy is estimated to be between 150 keV and 230 keV. Two possible scenaria on ULF wave triggering are discussed: vortex-like flow structure-driven field line resonance and ULF wave growth through drift resonance. It is found that the IP shock may trigger intense ULF wave and energetic electron behavior at L\~3 to 6 on the nightside, while the time profile of the wave is different from dayside cases.

Hao, Y.; Zong, Q.-G.; Wang, Y.; Zhou, X.-Z.; Zhang, Hui; Fu, S; Pu, Z; Spence, H.; Blake, J.; Bonnell, J.; Wygant, J.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020023

energetic particles; interplanetary shock; magnetotail ULF wave; poloidal and toroidal mode; Van Allen Probes; wave-particle interactions

Interactions of energetic electrons with ULF waves triggered by interplanetary shock: Van Allen Probes observations in the magnetotail

We present in situ observations of a shock-induced substorm-like event on 13 April 2013 observed by the newly launched Van Allen twin probes. Substorm-like electron injections with energy of 30\textendash500 keV were observed in the region from L\~5.2 to 5.5 immediately after the shock arrival (followed by energetic electron drift echoes). Meanwhile, the electron flux was clearly and strongly varying on the ULF wave time scale. It is found that both toroidal and poloidal mode ULF waves with a period of 150 s emerged following the magnetotail magnetic field reconfiguration after the interplanetary (IP) shock passage. The poloidal mode is more intense than the toroidal mode. The 90\textdegree phase shift between the poloidal mode Br and Ea suggests the standing poloidal waves in the Northern Hemisphere. Furthermore, the energetic electron flux modulations indicate that the azimuthal wave number is \~14. Direct evidence of drift resonance between the injected electrons and the excited poloidal ULF wave has been obtained. The resonant energy is estimated to be between 150 keV and 230 keV. Two possible scenaria on ULF wave triggering are discussed: vortex-like flow structure-driven field line resonance and ULF wave growth through drift resonance. It is found that the IP shock may trigger intense ULF wave and energetic electron behavior at L\~3 to 6 on the nightside, while the time profile of the wave is different from dayside cases.

Hao, Y.; Zong, Q.-G.; Wang, Y.; Zhou, X.-Z.; Zhang, Hui; Fu, S; Pu, Z; Spence, H.; Blake, J.; Bonnell, J.; Wygant, J.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014JA020023

energetic particles; interplanetary shock; magnetotail ULF wave; poloidal and toroidal mode; Van Allen Probes; wave-particle interactions

Modeling cross L shell impacts of magnetopause shadowing and ULF wave radial diffusion in the Van Allen belts

We present simulations of the outer electron radiation belt using a new ULF wave-driven radial diffusion model, including empirical representations of loss due to chorus and plasmaspheric hiss. With an outer boundary condition constrained by in situ electron flux observations, we focus on the impacts of magnetopause shadowing and outward radial diffusion in the heart of the radiation belt. Third invariant conserving solutions are combined to simulate the L shell and time dependence of the differential flux at a fixed energy. Results for the geomagnetically quiet year of 2008 demonstrate not only remarkable cross L shell impacts from magnetopause shadowing but also excellent agreement with the in situ observations even though no internal acceleration source is included in the model. Our model demonstrates powerful utility for capturing the cross-L impacts of magnetopause shadowing with significant prospects for improved space weather forecasting. The potential role of the plasmasphere in creating a third belt is also discussed.

Ozeke, Louis; Mann, Ian; Turner, Drew; Murphy, Kyle; Degeling, Alex; Rae, Jonathan; Milling, David;

Published by: Geophysical Research Letters      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014GL060787

magnetopause shadowing; Radiation belt; ULF wave radial diffusion

Modeling cross L shell impacts of magnetopause shadowing and ULF wave radial diffusion in the Van Allen belts

We present simulations of the outer electron radiation belt using a new ULF wave-driven radial diffusion model, including empirical representations of loss due to chorus and plasmaspheric hiss. With an outer boundary condition constrained by in situ electron flux observations, we focus on the impacts of magnetopause shadowing and outward radial diffusion in the heart of the radiation belt. Third invariant conserving solutions are combined to simulate the L shell and time dependence of the differential flux at a fixed energy. Results for the geomagnetically quiet year of 2008 demonstrate not only remarkable cross L shell impacts from magnetopause shadowing but also excellent agreement with the in situ observations even though no internal acceleration source is included in the model. Our model demonstrates powerful utility for capturing the cross-L impacts of magnetopause shadowing with significant prospects for improved space weather forecasting. The potential role of the plasmasphere in creating a third belt is also discussed.

Ozeke, Louis; Mann, Ian; Turner, Drew; Murphy, Kyle; Degeling, Alex; Rae, Jonathan; Milling, David;

Published by: Geophysical Research Letters      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014GL060787

magnetopause shadowing; Radiation belt; ULF wave radial diffusion

Modeling cross L shell impacts of magnetopause shadowing and ULF wave radial diffusion in the Van Allen belts

We present simulations of the outer electron radiation belt using a new ULF wave-driven radial diffusion model, including empirical representations of loss due to chorus and plasmaspheric hiss. With an outer boundary condition constrained by in situ electron flux observations, we focus on the impacts of magnetopause shadowing and outward radial diffusion in the heart of the radiation belt. Third invariant conserving solutions are combined to simulate the L shell and time dependence of the differential flux at a fixed energy. Results for the geomagnetically quiet year of 2008 demonstrate not only remarkable cross L shell impacts from magnetopause shadowing but also excellent agreement with the in situ observations even though no internal acceleration source is included in the model. Our model demonstrates powerful utility for capturing the cross-L impacts of magnetopause shadowing with significant prospects for improved space weather forecasting. The potential role of the plasmasphere in creating a third belt is also discussed.

Ozeke, Louis; Mann, Ian; Turner, Drew; Murphy, Kyle; Degeling, Alex; Rae, Jonathan; Milling, David;

Published by: Geophysical Research Letters      Published on: 10/2014

YEAR: 2014     DOI: 10.1002/2014GL060787

magnetopause shadowing; Radiation belt; ULF wave radial diffusion