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Found 4151 entries in the Bibliography.
Showing entries from 2301 through 2350
| 2016 |
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In this paper we review recent spacecraft observations of oblique whistler-mode waves in the Earth\textquoterights inner magnetosphere as well as the various consequences of the presence of such waves for electron scattering and acceleration. In particular, we survey the statistics of occurrences and intensity of oblique chorus waves in the region of the outer radiation belt, comprised between the plasmapause and geostationary orbit, and discuss how their actual distribution may be explained by a combination of linear and non-linear generation, propagation, and damping processes. We further examine how such oblique wave populations can be included into both quasi-linear diffusion models and fully nonlinear models of wave-particle interaction. On this basis, we demonstrate that varying amounts of oblique waves can significantly change the rates of particle scattering, acceleration, and precipitation into the atmosphere during quiet times as well as in the course of a storm. Finally, we discuss possible generation mechanisms for such oblique waves in the radiation belts. We demonstrate that oblique whistler-mode chorus waves can be considered as an important ingredient of the radiation belt system and can play a key role in many aspects of wave-particle resonant interactions. Artemyev, Anton; Agapitov, Oleksiy; Mourenas, Didier; Krasnoselskikh, Vladimir; Shastun, Vitalii; Mozer, Forrest; Published by: Space Science Reviews Published on: 04/2016 YEAR: 2016 DOI: 10.1007/s11214-016-0252-5 Earth radiation belts; Van Allen Probes; Wave-particle interaction; Whistler waves |
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In this paper we review recent spacecraft observations of oblique whistler-mode waves in the Earth\textquoterights inner magnetosphere as well as the various consequences of the presence of such waves for electron scattering and acceleration. In particular, we survey the statistics of occurrences and intensity of oblique chorus waves in the region of the outer radiation belt, comprised between the plasmapause and geostationary orbit, and discuss how their actual distribution may be explained by a combination of linear and non-linear generation, propagation, and damping processes. We further examine how such oblique wave populations can be included into both quasi-linear diffusion models and fully nonlinear models of wave-particle interaction. On this basis, we demonstrate that varying amounts of oblique waves can significantly change the rates of particle scattering, acceleration, and precipitation into the atmosphere during quiet times as well as in the course of a storm. Finally, we discuss possible generation mechanisms for such oblique waves in the radiation belts. We demonstrate that oblique whistler-mode chorus waves can be considered as an important ingredient of the radiation belt system and can play a key role in many aspects of wave-particle resonant interactions. Artemyev, Anton; Agapitov, Oleksiy; Mourenas, Didier; Krasnoselskikh, Vladimir; Shastun, Vitalii; Mozer, Forrest; Published by: Space Science Reviews Published on: 04/2016 YEAR: 2016 DOI: 10.1007/s11214-016-0252-5 Earth radiation belts; Van Allen Probes; Wave-particle interaction; Whistler waves |
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In this paper we review recent spacecraft observations of oblique whistler-mode waves in the Earth\textquoterights inner magnetosphere as well as the various consequences of the presence of such waves for electron scattering and acceleration. In particular, we survey the statistics of occurrences and intensity of oblique chorus waves in the region of the outer radiation belt, comprised between the plasmapause and geostationary orbit, and discuss how their actual distribution may be explained by a combination of linear and non-linear generation, propagation, and damping processes. We further examine how such oblique wave populations can be included into both quasi-linear diffusion models and fully nonlinear models of wave-particle interaction. On this basis, we demonstrate that varying amounts of oblique waves can significantly change the rates of particle scattering, acceleration, and precipitation into the atmosphere during quiet times as well as in the course of a storm. Finally, we discuss possible generation mechanisms for such oblique waves in the radiation belts. We demonstrate that oblique whistler-mode chorus waves can be considered as an important ingredient of the radiation belt system and can play a key role in many aspects of wave-particle resonant interactions. Artemyev, Anton; Agapitov, Oleksiy; Mourenas, Didier; Krasnoselskikh, Vladimir; Shastun, Vitalii; Mozer, Forrest; Published by: Space Science Reviews Published on: 04/2016 YEAR: 2016 DOI: 10.1007/s11214-016-0252-5 Earth radiation belts; Van Allen Probes; Wave-particle interaction; Whistler waves |
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In this paper we review recent spacecraft observations of oblique whistler-mode waves in the Earth\textquoterights inner magnetosphere as well as the various consequences of the presence of such waves for electron scattering and acceleration. In particular, we survey the statistics of occurrences and intensity of oblique chorus waves in the region of the outer radiation belt, comprised between the plasmapause and geostationary orbit, and discuss how their actual distribution may be explained by a combination of linear and non-linear generation, propagation, and damping processes. We further examine how such oblique wave populations can be included into both quasi-linear diffusion models and fully nonlinear models of wave-particle interaction. On this basis, we demonstrate that varying amounts of oblique waves can significantly change the rates of particle scattering, acceleration, and precipitation into the atmosphere during quiet times as well as in the course of a storm. Finally, we discuss possible generation mechanisms for such oblique waves in the radiation belts. We demonstrate that oblique whistler-mode chorus waves can be considered as an important ingredient of the radiation belt system and can play a key role in many aspects of wave-particle resonant interactions. Artemyev, Anton; Agapitov, Oleksiy; Mourenas, Didier; Krasnoselskikh, Vladimir; Shastun, Vitalii; Mozer, Forrest; Published by: Space Science Reviews Published on: 04/2016 YEAR: 2016 DOI: 10.1007/s11214-016-0252-5 Earth radiation belts; Van Allen Probes; Wave-particle interaction; Whistler waves |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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Ring current electron dynamics during geomagnetic storms based on the Van Allen Probes measurements Based on comprehensive measurements from Helium, Oxygen, Proton, and Electron Mass Spectrometer Ion Spectrometer, Relativistic Electron-Proton Telescope, and Radiation Belt Storm Probes Ion Composition Experiment instruments on the Van Allen Probes, comparative studies of ring current electrons and ions are performed and the role of energetic electrons in the ring current dynamics is investigated. The deep injections of tens to hundreds of keV electrons and tens of keV protons into the inner magnetosphere occur frequently; after the injections the electrons decay slowly in the inner belt but protons in the low L region decay very fast. Intriguing similarities between lower energy protons and higher-energy electrons are also found. The evolution of ring current electron and ion energy densities and energy content are examined in detail during two geomagnetic storms, one moderate and one intense. The results show that the contribution of ring current electrons to the ring current energy content is much smaller than that of ring current ions (up to ~12\% for the moderate storm and ~7\% for the intense storm), and <35 keV electrons dominate the ring current electron energy content at the storm main phases. Though the electron energy content is usually much smaller than that of ions, the enhancement of ring current electron energy content during the moderate storm can get to ~30\% of that of ring current ions, indicating a more dynamic feature of ring current electrons and important role of electrons in the ring current buildup. The ring current electron energy density is also shown to be higher at midnight and dawn while lower at noon and dusk. Zhao, H.; Li, X.; Baker, D.; Claudepierre, S.; Fennell, J.; Blake, J.; Larsen, B.; Skoug, R.; Funsten, H.; Friedel, R.; Reeves, G.; Spence, H.; Mitchell, D.; Lanzerotti, L.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022358 deep injections; Geomagnetic storms; ring current; ring current energy content; ring current electrons; Van Allen Probes |
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The Van Allen Probe observations during the recovery phase of a large storm that occurred on 17 March 2015 showed that the ultrarelativistic electrons at the inner boundary of the outer radiation belt (L* = 2.6\textendash3.7) exhibited butterfly pitch angle distributions, while the inner belt and the slot region also showed evidence of sub-MeV electron butterfly distributions. Strong magnetosonic waves were observed in the same regions and at the same time periods as these butterfly distributions. Moreover, when these magnetosonic waves extended to higher altitudes (L* = 4.1), the butterfly distributions also extended to the same region. Combining test particle calculations and Fokker-Planck diffusion simulations, we successfully reproduced the formation of the ultrarelativistic electron butterfly distributions, which primarily result from parallel acceleration caused by Landau resonance with magnetosonic waves. The coexistence of ultrarelativistic electron butterfly distributions with magnetosonic waves was also observed in the 24 June 2015 storm, providing further support that the magnetosonic waves play a key role in forming butterfly distributions. Li, Jinxing; Bortnik, Jacob; Thorne, Richard; Li, Wen; Ma, Qianli; Baker, Daniel; Reeves, Geoffrey; Fennell, Joseph; Spence, Harlan; Kletzing, Craig; Kurth, William; Hospodarsky, George; Angelopoulos, Vassilis; Blake, Bernard.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022370 butterfly distributions; Landau resonance; magnetosonic waves; Radiation belt; Van Allen Probes |
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The Van Allen Probe observations during the recovery phase of a large storm that occurred on 17 March 2015 showed that the ultrarelativistic electrons at the inner boundary of the outer radiation belt (L* = 2.6\textendash3.7) exhibited butterfly pitch angle distributions, while the inner belt and the slot region also showed evidence of sub-MeV electron butterfly distributions. Strong magnetosonic waves were observed in the same regions and at the same time periods as these butterfly distributions. Moreover, when these magnetosonic waves extended to higher altitudes (L* = 4.1), the butterfly distributions also extended to the same region. Combining test particle calculations and Fokker-Planck diffusion simulations, we successfully reproduced the formation of the ultrarelativistic electron butterfly distributions, which primarily result from parallel acceleration caused by Landau resonance with magnetosonic waves. The coexistence of ultrarelativistic electron butterfly distributions with magnetosonic waves was also observed in the 24 June 2015 storm, providing further support that the magnetosonic waves play a key role in forming butterfly distributions. Li, Jinxing; Bortnik, Jacob; Thorne, Richard; Li, Wen; Ma, Qianli; Baker, Daniel; Reeves, Geoffrey; Fennell, Joseph; Spence, Harlan; Kletzing, Craig; Kurth, William; Hospodarsky, George; Angelopoulos, Vassilis; Blake, Bernard.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022370 butterfly distributions; Landau resonance; magnetosonic waves; Radiation belt; Van Allen Probes |
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The Van Allen Probe observations during the recovery phase of a large storm that occurred on 17 March 2015 showed that the ultrarelativistic electrons at the inner boundary of the outer radiation belt (L* = 2.6\textendash3.7) exhibited butterfly pitch angle distributions, while the inner belt and the slot region also showed evidence of sub-MeV electron butterfly distributions. Strong magnetosonic waves were observed in the same regions and at the same time periods as these butterfly distributions. Moreover, when these magnetosonic waves extended to higher altitudes (L* = 4.1), the butterfly distributions also extended to the same region. Combining test particle calculations and Fokker-Planck diffusion simulations, we successfully reproduced the formation of the ultrarelativistic electron butterfly distributions, which primarily result from parallel acceleration caused by Landau resonance with magnetosonic waves. The coexistence of ultrarelativistic electron butterfly distributions with magnetosonic waves was also observed in the 24 June 2015 storm, providing further support that the magnetosonic waves play a key role in forming butterfly distributions. Li, Jinxing; Bortnik, Jacob; Thorne, Richard; Li, Wen; Ma, Qianli; Baker, Daniel; Reeves, Geoffrey; Fennell, Joseph; Spence, Harlan; Kletzing, Craig; Kurth, William; Hospodarsky, George; Angelopoulos, Vassilis; Blake, Bernard.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022370 butterfly distributions; Landau resonance; magnetosonic waves; Radiation belt; Van Allen Probes |
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The Van Allen Probe observations during the recovery phase of a large storm that occurred on 17 March 2015 showed that the ultrarelativistic electrons at the inner boundary of the outer radiation belt (L* = 2.6\textendash3.7) exhibited butterfly pitch angle distributions, while the inner belt and the slot region also showed evidence of sub-MeV electron butterfly distributions. Strong magnetosonic waves were observed in the same regions and at the same time periods as these butterfly distributions. Moreover, when these magnetosonic waves extended to higher altitudes (L* = 4.1), the butterfly distributions also extended to the same region. Combining test particle calculations and Fokker-Planck diffusion simulations, we successfully reproduced the formation of the ultrarelativistic electron butterfly distributions, which primarily result from parallel acceleration caused by Landau resonance with magnetosonic waves. The coexistence of ultrarelativistic electron butterfly distributions with magnetosonic waves was also observed in the 24 June 2015 storm, providing further support that the magnetosonic waves play a key role in forming butterfly distributions. Li, Jinxing; Bortnik, Jacob; Thorne, Richard; Li, Wen; Ma, Qianli; Baker, Daniel; Reeves, Geoffrey; Fennell, Joseph; Spence, Harlan; Kletzing, Craig; Kurth, William; Hospodarsky, George; Angelopoulos, Vassilis; Blake, Bernard.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022370 butterfly distributions; Landau resonance; magnetosonic waves; Radiation belt; Van Allen Probes |
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The Van Allen Probe observations during the recovery phase of a large storm that occurred on 17 March 2015 showed that the ultrarelativistic electrons at the inner boundary of the outer radiation belt (L* = 2.6\textendash3.7) exhibited butterfly pitch angle distributions, while the inner belt and the slot region also showed evidence of sub-MeV electron butterfly distributions. Strong magnetosonic waves were observed in the same regions and at the same time periods as these butterfly distributions. Moreover, when these magnetosonic waves extended to higher altitudes (L* = 4.1), the butterfly distributions also extended to the same region. Combining test particle calculations and Fokker-Planck diffusion simulations, we successfully reproduced the formation of the ultrarelativistic electron butterfly distributions, which primarily result from parallel acceleration caused by Landau resonance with magnetosonic waves. The coexistence of ultrarelativistic electron butterfly distributions with magnetosonic waves was also observed in the 24 June 2015 storm, providing further support that the magnetosonic waves play a key role in forming butterfly distributions. Li, Jinxing; Bortnik, Jacob; Thorne, Richard; Li, Wen; Ma, Qianli; Baker, Daniel; Reeves, Geoffrey; Fennell, Joseph; Spence, Harlan; Kletzing, Craig; Kurth, William; Hospodarsky, George; Angelopoulos, Vassilis; Blake, Bernard.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022370 butterfly distributions; Landau resonance; magnetosonic waves; Radiation belt; Van Allen Probes |
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The Van Allen Probe observations during the recovery phase of a large storm that occurred on 17 March 2015 showed that the ultrarelativistic electrons at the inner boundary of the outer radiation belt (L* = 2.6\textendash3.7) exhibited butterfly pitch angle distributions, while the inner belt and the slot region also showed evidence of sub-MeV electron butterfly distributions. Strong magnetosonic waves were observed in the same regions and at the same time periods as these butterfly distributions. Moreover, when these magnetosonic waves extended to higher altitudes (L* = 4.1), the butterfly distributions also extended to the same region. Combining test particle calculations and Fokker-Planck diffusion simulations, we successfully reproduced the formation of the ultrarelativistic electron butterfly distributions, which primarily result from parallel acceleration caused by Landau resonance with magnetosonic waves. The coexistence of ultrarelativistic electron butterfly distributions with magnetosonic waves was also observed in the 24 June 2015 storm, providing further support that the magnetosonic waves play a key role in forming butterfly distributions. Li, Jinxing; Bortnik, Jacob; Thorne, Richard; Li, Wen; Ma, Qianli; Baker, Daniel; Reeves, Geoffrey; Fennell, Joseph; Spence, Harlan; Kletzing, Craig; Kurth, William; Hospodarsky, George; Angelopoulos, Vassilis; Blake, Bernard.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022370 butterfly distributions; Landau resonance; magnetosonic waves; Radiation belt; Van Allen Probes |
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The Van Allen Probe observations during the recovery phase of a large storm that occurred on 17 March 2015 showed that the ultrarelativistic electrons at the inner boundary of the outer radiation belt (L* = 2.6\textendash3.7) exhibited butterfly pitch angle distributions, while the inner belt and the slot region also showed evidence of sub-MeV electron butterfly distributions. Strong magnetosonic waves were observed in the same regions and at the same time periods as these butterfly distributions. Moreover, when these magnetosonic waves extended to higher altitudes (L* = 4.1), the butterfly distributions also extended to the same region. Combining test particle calculations and Fokker-Planck diffusion simulations, we successfully reproduced the formation of the ultrarelativistic electron butterfly distributions, which primarily result from parallel acceleration caused by Landau resonance with magnetosonic waves. The coexistence of ultrarelativistic electron butterfly distributions with magnetosonic waves was also observed in the 24 June 2015 storm, providing further support that the magnetosonic waves play a key role in forming butterfly distributions. Li, Jinxing; Bortnik, Jacob; Thorne, Richard; Li, Wen; Ma, Qianli; Baker, Daniel; Reeves, Geoffrey; Fennell, Joseph; Spence, Harlan; Kletzing, Craig; Kurth, William; Hospodarsky, George; Angelopoulos, Vassilis; Blake, Bernard.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022370 butterfly distributions; Landau resonance; magnetosonic waves; Radiation belt; Van Allen Probes |
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The Van Allen Probe observations during the recovery phase of a large storm that occurred on 17 March 2015 showed that the ultrarelativistic electrons at the inner boundary of the outer radiation belt (L* = 2.6\textendash3.7) exhibited butterfly pitch angle distributions, while the inner belt and the slot region also showed evidence of sub-MeV electron butterfly distributions. Strong magnetosonic waves were observed in the same regions and at the same time periods as these butterfly distributions. Moreover, when these magnetosonic waves extended to higher altitudes (L* = 4.1), the butterfly distributions also extended to the same region. Combining test particle calculations and Fokker-Planck diffusion simulations, we successfully reproduced the formation of the ultrarelativistic electron butterfly distributions, which primarily result from parallel acceleration caused by Landau resonance with magnetosonic waves. The coexistence of ultrarelativistic electron butterfly distributions with magnetosonic waves was also observed in the 24 June 2015 storm, providing further support that the magnetosonic waves play a key role in forming butterfly distributions. Li, Jinxing; Bortnik, Jacob; Thorne, Richard; Li, Wen; Ma, Qianli; Baker, Daniel; Reeves, Geoffrey; Fennell, Joseph; Spence, Harlan; Kletzing, Craig; Kurth, William; Hospodarsky, George; Angelopoulos, Vassilis; Blake, Bernard.; Published by: Journal of Geophysical Research: Space Physics Published on: 04/2016 YEAR: 2016 DOI: 10.1002/2016JA022370 butterfly distributions; Landau resonance; magnetosonic waves; Radiation belt; Van Allen Probes |
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Ultralow frequency (ULF) electromagnetic waves in Earth\textquoterights magnetosphere can accelerate charged particles via a process called drift resonance. In the conventional drift-resonance theory, a default assumption is that the wave growth rate is time-independent, positive, and extremely small. However, this is not the case for ULF waves in the real magnetosphere. The ULF waves must have experienced an earlier growth stage when their energy was taken from external and/or internal sources, and as time proceeds the waves have to be damped with a negative growth rate. Therefore, a more generalized theory on particle behavior during different stages of ULF wave evolution is required. In this paper, we introduce a time-dependent imaginary wave frequency to accommodate the growth and damping of the waves in the drift-resonance theory, so that the wave-particle interactions during the entire wave lifespan can be studied. We then predict from the generalized theory particle signatures during different stages of the wave evolution, which are consistent with observations from Van Allen Probes. The more generalized theory, therefore, provides new insights into ULF wave evolution and wave-particle interactions in the magnetosphere. Zhou, Xu-Zhi; Wang, Zi-Han; Zong, Qiu-Gang; Rankin, Robert; Kivelson, Margaret; Chen, Xing-Ran; Blake, Bernard; Wygant, John; Kletzing, Craig; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2016JA022447 drift resonance; Radiation belt; ULF waves; Van Allen Probes; wave growth and damping; Wave-particle interaction |
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Ultralow frequency (ULF) electromagnetic waves in Earth\textquoterights magnetosphere can accelerate charged particles via a process called drift resonance. In the conventional drift-resonance theory, a default assumption is that the wave growth rate is time-independent, positive, and extremely small. However, this is not the case for ULF waves in the real magnetosphere. The ULF waves must have experienced an earlier growth stage when their energy was taken from external and/or internal sources, and as time proceeds the waves have to be damped with a negative growth rate. Therefore, a more generalized theory on particle behavior during different stages of ULF wave evolution is required. In this paper, we introduce a time-dependent imaginary wave frequency to accommodate the growth and damping of the waves in the drift-resonance theory, so that the wave-particle interactions during the entire wave lifespan can be studied. We then predict from the generalized theory particle signatures during different stages of the wave evolution, which are consistent with observations from Van Allen Probes. The more generalized theory, therefore, provides new insights into ULF wave evolution and wave-particle interactions in the magnetosphere. Zhou, Xu-Zhi; Wang, Zi-Han; Zong, Qiu-Gang; Rankin, Robert; Kivelson, Margaret; Chen, Xing-Ran; Blake, Bernard; Wygant, John; Kletzing, Craig; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2016JA022447 drift resonance; Radiation belt; ULF waves; Van Allen Probes; wave growth and damping; Wave-particle interaction |
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Ultralow frequency (ULF) electromagnetic waves in Earth\textquoterights magnetosphere can accelerate charged particles via a process called drift resonance. In the conventional drift-resonance theory, a default assumption is that the wave growth rate is time-independent, positive, and extremely small. However, this is not the case for ULF waves in the real magnetosphere. The ULF waves must have experienced an earlier growth stage when their energy was taken from external and/or internal sources, and as time proceeds the waves have to be damped with a negative growth rate. Therefore, a more generalized theory on particle behavior during different stages of ULF wave evolution is required. In this paper, we introduce a time-dependent imaginary wave frequency to accommodate the growth and damping of the waves in the drift-resonance theory, so that the wave-particle interactions during the entire wave lifespan can be studied. We then predict from the generalized theory particle signatures during different stages of the wave evolution, which are consistent with observations from Van Allen Probes. The more generalized theory, therefore, provides new insights into ULF wave evolution and wave-particle interactions in the magnetosphere. Zhou, Xu-Zhi; Wang, Zi-Han; Zong, Qiu-Gang; Rankin, Robert; Kivelson, Margaret; Chen, Xing-Ran; Blake, Bernard; Wygant, John; Kletzing, Craig; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2016JA022447 drift resonance; Radiation belt; ULF waves; Van Allen Probes; wave growth and damping; Wave-particle interaction |
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Ultralow frequency (ULF) electromagnetic waves in Earth\textquoterights magnetosphere can accelerate charged particles via a process called drift resonance. In the conventional drift-resonance theory, a default assumption is that the wave growth rate is time-independent, positive, and extremely small. However, this is not the case for ULF waves in the real magnetosphere. The ULF waves must have experienced an earlier growth stage when their energy was taken from external and/or internal sources, and as time proceeds the waves have to be damped with a negative growth rate. Therefore, a more generalized theory on particle behavior during different stages of ULF wave evolution is required. In this paper, we introduce a time-dependent imaginary wave frequency to accommodate the growth and damping of the waves in the drift-resonance theory, so that the wave-particle interactions during the entire wave lifespan can be studied. We then predict from the generalized theory particle signatures during different stages of the wave evolution, which are consistent with observations from Van Allen Probes. The more generalized theory, therefore, provides new insights into ULF wave evolution and wave-particle interactions in the magnetosphere. Zhou, Xu-Zhi; Wang, Zi-Han; Zong, Qiu-Gang; Rankin, Robert; Kivelson, Margaret; Chen, Xing-Ran; Blake, Bernard; Wygant, John; Kletzing, Craig; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2016JA022447 drift resonance; Radiation belt; ULF waves; Van Allen Probes; wave growth and damping; Wave-particle interaction |
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Inward diffusion and loss of radiation belt protons Radiation belt protons in the kinetic energy range 24 to 76 MeV are being measured by the Relativistic Electron Proton Telescope on each of the two Van Allen Probes. Data have been processed for the purpose of studying variability in the trapped proton intensity during October 2013 to August 2015. For the lower energies (≲32 MeV), equatorial proton intensity near L = 2 showed a steady increase that is consistent with inward diffusion of trapped solar protons, as shown by positive radial gradients in phase space density at fixed values of the first two adiabatic invariants. It is postulated that these protons were trapped with enhanced efficiency during the 7 March 2012 solar proton event. A model that includes radial diffusion, along with known trapped proton source and loss processes, shows that the observed average rate of increase near L = 2 is predicted by the same model diffusion coefficient that is required to form the entire proton radiation belt, down to low L, over an extended (\~103 year) interval. A slower intensity decrease for lower energies near L = 1.5 may also be caused by inward diffusion, though it is faster than predicted by the model. Higher-energy (≳40 MeV) protons near the L = 1.5 intensity maximum are from cosmic ray albedo neutron decay. Their observed intensity is lower than expected by a factor \~2, but the discrepancy is resolved by adding an unspecified loss process to the model with a mean lifetime \~120 years. Selesnick, R.; Baker, D.; Jaynes, A.; Li, X.; Kanekal, S.; Hudson, M.; Kress, B.; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2015JA022154 |
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Inward diffusion and loss of radiation belt protons Radiation belt protons in the kinetic energy range 24 to 76 MeV are being measured by the Relativistic Electron Proton Telescope on each of the two Van Allen Probes. Data have been processed for the purpose of studying variability in the trapped proton intensity during October 2013 to August 2015. For the lower energies (≲32 MeV), equatorial proton intensity near L = 2 showed a steady increase that is consistent with inward diffusion of trapped solar protons, as shown by positive radial gradients in phase space density at fixed values of the first two adiabatic invariants. It is postulated that these protons were trapped with enhanced efficiency during the 7 March 2012 solar proton event. A model that includes radial diffusion, along with known trapped proton source and loss processes, shows that the observed average rate of increase near L = 2 is predicted by the same model diffusion coefficient that is required to form the entire proton radiation belt, down to low L, over an extended (\~103 year) interval. A slower intensity decrease for lower energies near L = 1.5 may also be caused by inward diffusion, though it is faster than predicted by the model. Higher-energy (≳40 MeV) protons near the L = 1.5 intensity maximum are from cosmic ray albedo neutron decay. Their observed intensity is lower than expected by a factor \~2, but the discrepancy is resolved by adding an unspecified loss process to the model with a mean lifetime \~120 years. Selesnick, R.; Baker, D.; Jaynes, A.; Li, X.; Kanekal, S.; Hudson, M.; Kress, B.; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2015JA022154 |
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Inward diffusion and loss of radiation belt protons Radiation belt protons in the kinetic energy range 24 to 76 MeV are being measured by the Relativistic Electron Proton Telescope on each of the two Van Allen Probes. Data have been processed for the purpose of studying variability in the trapped proton intensity during October 2013 to August 2015. For the lower energies (≲32 MeV), equatorial proton intensity near L = 2 showed a steady increase that is consistent with inward diffusion of trapped solar protons, as shown by positive radial gradients in phase space density at fixed values of the first two adiabatic invariants. It is postulated that these protons were trapped with enhanced efficiency during the 7 March 2012 solar proton event. A model that includes radial diffusion, along with known trapped proton source and loss processes, shows that the observed average rate of increase near L = 2 is predicted by the same model diffusion coefficient that is required to form the entire proton radiation belt, down to low L, over an extended (\~103 year) interval. A slower intensity decrease for lower energies near L = 1.5 may also be caused by inward diffusion, though it is faster than predicted by the model. Higher-energy (≳40 MeV) protons near the L = 1.5 intensity maximum are from cosmic ray albedo neutron decay. Their observed intensity is lower than expected by a factor \~2, but the discrepancy is resolved by adding an unspecified loss process to the model with a mean lifetime \~120 years. Selesnick, R.; Baker, D.; Jaynes, A.; Li, X.; Kanekal, S.; Hudson, M.; Kress, B.; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2015JA022154 |
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Inward diffusion and loss of radiation belt protons Radiation belt protons in the kinetic energy range 24 to 76 MeV are being measured by the Relativistic Electron Proton Telescope on each of the two Van Allen Probes. Data have been processed for the purpose of studying variability in the trapped proton intensity during October 2013 to August 2015. For the lower energies (≲32 MeV), equatorial proton intensity near L = 2 showed a steady increase that is consistent with inward diffusion of trapped solar protons, as shown by positive radial gradients in phase space density at fixed values of the first two adiabatic invariants. It is postulated that these protons were trapped with enhanced efficiency during the 7 March 2012 solar proton event. A model that includes radial diffusion, along with known trapped proton source and loss processes, shows that the observed average rate of increase near L = 2 is predicted by the same model diffusion coefficient that is required to form the entire proton radiation belt, down to low L, over an extended (\~103 year) interval. A slower intensity decrease for lower energies near L = 1.5 may also be caused by inward diffusion, though it is faster than predicted by the model. Higher-energy (≳40 MeV) protons near the L = 1.5 intensity maximum are from cosmic ray albedo neutron decay. Their observed intensity is lower than expected by a factor \~2, but the discrepancy is resolved by adding an unspecified loss process to the model with a mean lifetime \~120 years. Selesnick, R.; Baker, D.; Jaynes, A.; Li, X.; Kanekal, S.; Hudson, M.; Kress, B.; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2015JA022154 |
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Inward diffusion and loss of radiation belt protons Radiation belt protons in the kinetic energy range 24 to 76 MeV are being measured by the Relativistic Electron Proton Telescope on each of the two Van Allen Probes. Data have been processed for the purpose of studying variability in the trapped proton intensity during October 2013 to August 2015. For the lower energies (≲32 MeV), equatorial proton intensity near L = 2 showed a steady increase that is consistent with inward diffusion of trapped solar protons, as shown by positive radial gradients in phase space density at fixed values of the first two adiabatic invariants. It is postulated that these protons were trapped with enhanced efficiency during the 7 March 2012 solar proton event. A model that includes radial diffusion, along with known trapped proton source and loss processes, shows that the observed average rate of increase near L = 2 is predicted by the same model diffusion coefficient that is required to form the entire proton radiation belt, down to low L, over an extended (\~103 year) interval. A slower intensity decrease for lower energies near L = 1.5 may also be caused by inward diffusion, though it is faster than predicted by the model. Higher-energy (≳40 MeV) protons near the L = 1.5 intensity maximum are from cosmic ray albedo neutron decay. Their observed intensity is lower than expected by a factor \~2, but the discrepancy is resolved by adding an unspecified loss process to the model with a mean lifetime \~120 years. Selesnick, R.; Baker, D.; Jaynes, A.; Li, X.; Kanekal, S.; Hudson, M.; Kress, B.; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2015JA022154 |
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Lightning-generated whistler waves are electromagnetic plasma waves in the very low frequency (VLF) band, which play an important role in the dynamics of radiation belt particles. In this paper, we statistically analyze simultaneous waveform data from the Van Allen Probes (Radiation Belt Storm Probes, RBSP) and global lightning data from the World Wide Lightning Location Network (WWLLN). Data were obtained between July to September 2013 and between March and April 2014. For each day during these periods, we predicted the most probable 10 min for which each of the two RBSP satellites would be magnetically conjugate to lightning producing regions. The prediction method uses integrated WWLLN stroke data for that day obtained during the three previous years. Using these predicted times for magnetic conjugacy to lightning activity regions, we recorded high time resolution, burst mode waveform data. Here we show that whistlers are observed by the satellites in more than 80\% of downloaded waveform data. About 22.9\% of the whistlers observed by RBSP are one-to-one coincident with source lightning strokes detected by WWLLN. About 40.1\% more of whistlers are found to be one-to-one coincident with lightning if source regions are extended out 2000 km from the satellites footpoints. Lightning strokes with far-field radiated VLF energy larger than about 100 J are able to generate a detectable whistler wave in the inner magnetosphere. One-to-one coincidences between whistlers observed by RBSP and lightning strokes detected by WWLLN are clearly shown in the L shell range of L = 1\textendash3. Nose whistlers observed in July 2014 show that it may be possible to extend this coincidence to the region of L>=4. Zheng, Hao; Holzworth, Robert; Brundell, James; Jacobson, Abram; Wygant, John; Hospodarsky, George; Mozer, Forrest; Bonnell, John; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2015JA022010 |
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Lightning-generated whistler waves are electromagnetic plasma waves in the very low frequency (VLF) band, which play an important role in the dynamics of radiation belt particles. In this paper, we statistically analyze simultaneous waveform data from the Van Allen Probes (Radiation Belt Storm Probes, RBSP) and global lightning data from the World Wide Lightning Location Network (WWLLN). Data were obtained between July to September 2013 and between March and April 2014. For each day during these periods, we predicted the most probable 10 min for which each of the two RBSP satellites would be magnetically conjugate to lightning producing regions. The prediction method uses integrated WWLLN stroke data for that day obtained during the three previous years. Using these predicted times for magnetic conjugacy to lightning activity regions, we recorded high time resolution, burst mode waveform data. Here we show that whistlers are observed by the satellites in more than 80\% of downloaded waveform data. About 22.9\% of the whistlers observed by RBSP are one-to-one coincident with source lightning strokes detected by WWLLN. About 40.1\% more of whistlers are found to be one-to-one coincident with lightning if source regions are extended out 2000 km from the satellites footpoints. Lightning strokes with far-field radiated VLF energy larger than about 100 J are able to generate a detectable whistler wave in the inner magnetosphere. One-to-one coincidences between whistlers observed by RBSP and lightning strokes detected by WWLLN are clearly shown in the L shell range of L = 1\textendash3. Nose whistlers observed in July 2014 show that it may be possible to extend this coincidence to the region of L>=4. Zheng, Hao; Holzworth, Robert; Brundell, James; Jacobson, Abram; Wygant, John; Hospodarsky, George; Mozer, Forrest; Bonnell, John; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2015JA022010 |
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Lightning-generated whistler waves are electromagnetic plasma waves in the very low frequency (VLF) band, which play an important role in the dynamics of radiation belt particles. In this paper, we statistically analyze simultaneous waveform data from the Van Allen Probes (Radiation Belt Storm Probes, RBSP) and global lightning data from the World Wide Lightning Location Network (WWLLN). Data were obtained between July to September 2013 and between March and April 2014. For each day during these periods, we predicted the most probable 10 min for which each of the two RBSP satellites would be magnetically conjugate to lightning producing regions. The prediction method uses integrated WWLLN stroke data for that day obtained during the three previous years. Using these predicted times for magnetic conjugacy to lightning activity regions, we recorded high time resolution, burst mode waveform data. Here we show that whistlers are observed by the satellites in more than 80\% of downloaded waveform data. About 22.9\% of the whistlers observed by RBSP are one-to-one coincident with source lightning strokes detected by WWLLN. About 40.1\% more of whistlers are found to be one-to-one coincident with lightning if source regions are extended out 2000 km from the satellites footpoints. Lightning strokes with far-field radiated VLF energy larger than about 100 J are able to generate a detectable whistler wave in the inner magnetosphere. One-to-one coincidences between whistlers observed by RBSP and lightning strokes detected by WWLLN are clearly shown in the L shell range of L = 1\textendash3. Nose whistlers observed in July 2014 show that it may be possible to extend this coincidence to the region of L>=4. Zheng, Hao; Holzworth, Robert; Brundell, James; Jacobson, Abram; Wygant, John; Hospodarsky, George; Mozer, Forrest; Bonnell, John; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2015JA022010 |
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Lightning-generated whistler waves are electromagnetic plasma waves in the very low frequency (VLF) band, which play an important role in the dynamics of radiation belt particles. In this paper, we statistically analyze simultaneous waveform data from the Van Allen Probes (Radiation Belt Storm Probes, RBSP) and global lightning data from the World Wide Lightning Location Network (WWLLN). Data were obtained between July to September 2013 and between March and April 2014. For each day during these periods, we predicted the most probable 10 min for which each of the two RBSP satellites would be magnetically conjugate to lightning producing regions. The prediction method uses integrated WWLLN stroke data for that day obtained during the three previous years. Using these predicted times for magnetic conjugacy to lightning activity regions, we recorded high time resolution, burst mode waveform data. Here we show that whistlers are observed by the satellites in more than 80\% of downloaded waveform data. About 22.9\% of the whistlers observed by RBSP are one-to-one coincident with source lightning strokes detected by WWLLN. About 40.1\% more of whistlers are found to be one-to-one coincident with lightning if source regions are extended out 2000 km from the satellites footpoints. Lightning strokes with far-field radiated VLF energy larger than about 100 J are able to generate a detectable whistler wave in the inner magnetosphere. One-to-one coincidences between whistlers observed by RBSP and lightning strokes detected by WWLLN are clearly shown in the L shell range of L = 1\textendash3. Nose whistlers observed in July 2014 show that it may be possible to extend this coincidence to the region of L>=4. Zheng, Hao; Holzworth, Robert; Brundell, James; Jacobson, Abram; Wygant, John; Hospodarsky, George; Mozer, Forrest; Bonnell, John; Published by: Journal of Geophysical Research: Space Physics Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2015JA022010 |
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Our investigation of the long-term ring current proton pressure evolution in Earth\textquoterights inner magnetosphere based on Van Allen Probes data shows drastically different behavior of the low- and high- energy components of the ring current proton population with respect to the Sym-H index variation. We found that while the low-energy component of the protons (<80 keV) is strongly governed by convective timescales and is very well correlated with the absolute value of Sym-H index, the high-energy component (>100 keV) varies on much longer timescales and shows either no or anti-correlation with the absolute value of Sym-H index. Our study also shows that the contributions of the low- and high- energy protons to the inner magnetosphere energy content are comparable. Thus, our results conclusively demonstrate that proton dynamics, and as a result the energy budget in the inner magnetosphere, do not vary strictly on storm-time timescales as those are defined by the Sym-H index. Gkioulidou, Matina; Ukhorskiy, A.; Mitchell, D.; Lanzerotti, L.; Published by: Geophysical Research Letters Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2016GL068013 energy budget; Geomagnetic storms; inner magnetosphere; ring current; Van Allen Probes |
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Our investigation of the long-term ring current proton pressure evolution in Earth\textquoterights inner magnetosphere based on Van Allen Probes data shows drastically different behavior of the low- and high- energy components of the ring current proton population with respect to the Sym-H index variation. We found that while the low-energy component of the protons (<80 keV) is strongly governed by convective timescales and is very well correlated with the absolute value of Sym-H index, the high-energy component (>100 keV) varies on much longer timescales and shows either no or anti-correlation with the absolute value of Sym-H index. Our study also shows that the contributions of the low- and high- energy protons to the inner magnetosphere energy content are comparable. Thus, our results conclusively demonstrate that proton dynamics, and as a result the energy budget in the inner magnetosphere, do not vary strictly on storm-time timescales as those are defined by the Sym-H index. Gkioulidou, Matina; Ukhorskiy, A.; Mitchell, D.; Lanzerotti, L.; Published by: Geophysical Research Letters Published on: 03/2016 YEAR: 2016 DOI: 10.1002/2016GL068013 energy budget; Geomagnetic storms; inner magnetosphere; ring current; Van Allen Probes |
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A case study of shortwave radar observations of magnetospheric Pc5 ULF waves (wave periods of 150\textendash600 s) that occurred on 26 December 2014 in the nightside magnetosphere during substorm activity is presented. The radar study of waves in the magnetosphere is based on analysis of scattering from field-aligned irregularities of the ionospheric F layer. Variations of their inline image drift velocity at F layer heights are associated with the wave electric field. Analysis of the observations from the Ekaterinburg (EKB) radar shows that the frequency f of the observed wave depends on the azimuthal wave number m (positive correlation of about 0.90): an increase in frequency from 2.5 to 5 mHz corresponds to increased m number from 20 to 80. Of the known types of waves in the magnetosphere corresponding to the Pc5 range, only drift compressional waves have such azimuthal dispersion: the frequency of the drift compressional mode is directly proportional to the azimuthal wave number and the gradient-curvature drift velocity of energetic particles in the magnetic field. This wave has a kinetic nature and represents the most common kind of the compressional modes, demanding for its existence only finite pressure and plasma inhomogeneity across magnetic shells. Chelpanov, Maksim; Mager, Pavel; Klimushkin, Dmitri; Berngardt, Oleg; Mager, Olga; Published by: Journal of Geophysical Research: Space Physics Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015JA022155 |
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A case study of shortwave radar observations of magnetospheric Pc5 ULF waves (wave periods of 150\textendash600 s) that occurred on 26 December 2014 in the nightside magnetosphere during substorm activity is presented. The radar study of waves in the magnetosphere is based on analysis of scattering from field-aligned irregularities of the ionospheric F layer. Variations of their inline image drift velocity at F layer heights are associated with the wave electric field. Analysis of the observations from the Ekaterinburg (EKB) radar shows that the frequency f of the observed wave depends on the azimuthal wave number m (positive correlation of about 0.90): an increase in frequency from 2.5 to 5 mHz corresponds to increased m number from 20 to 80. Of the known types of waves in the magnetosphere corresponding to the Pc5 range, only drift compressional waves have such azimuthal dispersion: the frequency of the drift compressional mode is directly proportional to the azimuthal wave number and the gradient-curvature drift velocity of energetic particles in the magnetic field. This wave has a kinetic nature and represents the most common kind of the compressional modes, demanding for its existence only finite pressure and plasma inhomogeneity across magnetic shells. Chelpanov, Maksim; Mager, Pavel; Klimushkin, Dmitri; Berngardt, Oleg; Mager, Olga; Published by: Journal of Geophysical Research: Space Physics Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015JA022155 |
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A case study of shortwave radar observations of magnetospheric Pc5 ULF waves (wave periods of 150\textendash600 s) that occurred on 26 December 2014 in the nightside magnetosphere during substorm activity is presented. The radar study of waves in the magnetosphere is based on analysis of scattering from field-aligned irregularities of the ionospheric F layer. Variations of their inline image drift velocity at F layer heights are associated with the wave electric field. Analysis of the observations from the Ekaterinburg (EKB) radar shows that the frequency f of the observed wave depends on the azimuthal wave number m (positive correlation of about 0.90): an increase in frequency from 2.5 to 5 mHz corresponds to increased m number from 20 to 80. Of the known types of waves in the magnetosphere corresponding to the Pc5 range, only drift compressional waves have such azimuthal dispersion: the frequency of the drift compressional mode is directly proportional to the azimuthal wave number and the gradient-curvature drift velocity of energetic particles in the magnetic field. This wave has a kinetic nature and represents the most common kind of the compressional modes, demanding for its existence only finite pressure and plasma inhomogeneity across magnetic shells. Chelpanov, Maksim; Mager, Pavel; Klimushkin, Dmitri; Berngardt, Oleg; Mager, Olga; Published by: Journal of Geophysical Research: Space Physics Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015JA022155 |
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A case study of shortwave radar observations of magnetospheric Pc5 ULF waves (wave periods of 150\textendash600 s) that occurred on 26 December 2014 in the nightside magnetosphere during substorm activity is presented. The radar study of waves in the magnetosphere is based on analysis of scattering from field-aligned irregularities of the ionospheric F layer. Variations of their inline image drift velocity at F layer heights are associated with the wave electric field. Analysis of the observations from the Ekaterinburg (EKB) radar shows that the frequency f of the observed wave depends on the azimuthal wave number m (positive correlation of about 0.90): an increase in frequency from 2.5 to 5 mHz corresponds to increased m number from 20 to 80. Of the known types of waves in the magnetosphere corresponding to the Pc5 range, only drift compressional waves have such azimuthal dispersion: the frequency of the drift compressional mode is directly proportional to the azimuthal wave number and the gradient-curvature drift velocity of energetic particles in the magnetic field. This wave has a kinetic nature and represents the most common kind of the compressional modes, demanding for its existence only finite pressure and plasma inhomogeneity across magnetic shells. Chelpanov, Maksim; Mager, Pavel; Klimushkin, Dmitri; Berngardt, Oleg; Mager, Olga; Published by: Journal of Geophysical Research: Space Physics Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015JA022155 |
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Forecasting and remote sensing outer belt relativistic electrons from low Earth orbit This study demonstrates the feasibility and reliability of using observations from low Earth orbit (LEO) to forecast and nowcast relativistic electrons in the outer radiation belt. We first report a high cross-energy, cross-pitch-angle coherence discovered between the trapped MeV electrons and precipitating approximately hundreds (~100s) of keV electrons\textemdashobserved by satellites with very different altitudes\textemdashwith correlation coefficients as high as ≳ 0.85. Based upon the coherence, we then tested the feasibility of applying linear prediction filters to LEO data to predict the arrival of new MeV electrons during geomagnetic storms, as well as their evolving distributions afterward. Reliability of these predictive filters is quantified by the performance efficiency with values as high as 0.74 when driven merely by LEO observations (or up to 0.94 with the inclusion of in situ MeV electron measurements). Finally, a hypothesis based upon the wave-particle resonance theory is proposed to explain the coherence, and a first-principle electron tracing model yields supporting evidence. Chen, Yue; Reeves, Geoffrey; Cunningham, Gregory; Redmon, Robert; Henderson, Michael; Published by: Geophysical Research Letters Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015GL067481 forecast and nowcast; hundreds of keV precipitating electrons; LEO observations; Radiation belts; relativistic electrons; wave particle interactions |
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Forecasting and remote sensing outer belt relativistic electrons from low Earth orbit This study demonstrates the feasibility and reliability of using observations from low Earth orbit (LEO) to forecast and nowcast relativistic electrons in the outer radiation belt. We first report a high cross-energy, cross-pitch-angle coherence discovered between the trapped MeV electrons and precipitating approximately hundreds (~100s) of keV electrons\textemdashobserved by satellites with very different altitudes\textemdashwith correlation coefficients as high as ≳ 0.85. Based upon the coherence, we then tested the feasibility of applying linear prediction filters to LEO data to predict the arrival of new MeV electrons during geomagnetic storms, as well as their evolving distributions afterward. Reliability of these predictive filters is quantified by the performance efficiency with values as high as 0.74 when driven merely by LEO observations (or up to 0.94 with the inclusion of in situ MeV electron measurements). Finally, a hypothesis based upon the wave-particle resonance theory is proposed to explain the coherence, and a first-principle electron tracing model yields supporting evidence. Chen, Yue; Reeves, Geoffrey; Cunningham, Gregory; Redmon, Robert; Henderson, Michael; Published by: Geophysical Research Letters Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015GL067481 forecast and nowcast; hundreds of keV precipitating electrons; LEO observations; Radiation belts; relativistic electrons; wave particle interactions |
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Forecasting and remote sensing outer belt relativistic electrons from low Earth orbit This study demonstrates the feasibility and reliability of using observations from low Earth orbit (LEO) to forecast and nowcast relativistic electrons in the outer radiation belt. We first report a high cross-energy, cross-pitch-angle coherence discovered between the trapped MeV electrons and precipitating approximately hundreds (~100s) of keV electrons\textemdashobserved by satellites with very different altitudes\textemdashwith correlation coefficients as high as ≳ 0.85. Based upon the coherence, we then tested the feasibility of applying linear prediction filters to LEO data to predict the arrival of new MeV electrons during geomagnetic storms, as well as their evolving distributions afterward. Reliability of these predictive filters is quantified by the performance efficiency with values as high as 0.74 when driven merely by LEO observations (or up to 0.94 with the inclusion of in situ MeV electron measurements). Finally, a hypothesis based upon the wave-particle resonance theory is proposed to explain the coherence, and a first-principle electron tracing model yields supporting evidence. Chen, Yue; Reeves, Geoffrey; Cunningham, Gregory; Redmon, Robert; Henderson, Michael; Published by: Geophysical Research Letters Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015GL067481 forecast and nowcast; hundreds of keV precipitating electrons; LEO observations; Radiation belts; relativistic electrons; wave particle interactions |
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Forecasting and remote sensing outer belt relativistic electrons from low Earth orbit This study demonstrates the feasibility and reliability of using observations from low Earth orbit (LEO) to forecast and nowcast relativistic electrons in the outer radiation belt. We first report a high cross-energy, cross-pitch-angle coherence discovered between the trapped MeV electrons and precipitating approximately hundreds (~100s) of keV electrons\textemdashobserved by satellites with very different altitudes\textemdashwith correlation coefficients as high as ≳ 0.85. Based upon the coherence, we then tested the feasibility of applying linear prediction filters to LEO data to predict the arrival of new MeV electrons during geomagnetic storms, as well as their evolving distributions afterward. Reliability of these predictive filters is quantified by the performance efficiency with values as high as 0.74 when driven merely by LEO observations (or up to 0.94 with the inclusion of in situ MeV electron measurements). Finally, a hypothesis based upon the wave-particle resonance theory is proposed to explain the coherence, and a first-principle electron tracing model yields supporting evidence. Chen, Yue; Reeves, Geoffrey; Cunningham, Gregory; Redmon, Robert; Henderson, Michael; Published by: Geophysical Research Letters Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015GL067481 forecast and nowcast; hundreds of keV precipitating electrons; LEO observations; Radiation belts; relativistic electrons; wave particle interactions |
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Energetic electron observations in Earth\textquoterights radiation belts are typically sparse and multi-point studies often rely on serendipitous conjunctions. This paper establishes the scientific utility of the Combined X-ray Dosimeter (CXD), currently flown on 19 satellites in the Global Positioning System (GPS) constellation, by cross-calibrating energetic electron measurements against data from the Van Allen Probes. By breaking our cross-calibration into two parts \textendash one that removes any spectral assumptions from the CXD flux calculation, and one that compares the energy spectra \textendash we first validate the modeled instrument response functions, then the calculated electron fluxes. Unlike previous forward modeling of energetic electron spectra we use a combination of four distributions that, together, capture a wide range of observed spectral shapes. Our two-step approach allowed us to identify, and correct for, small systematic offsets between block IIR and IIF satellites. Using the Magnetic Electron Ion Spectrometer (MagEIS) and Relativistic Electron-Proton Telescope (REPT) on Van Allen Probes as a \textquotedblleftgold standard\textquotedblright we demonstrate that the CXD instruments are well-understood. A robust statistical analysis shows that CXD and Van Allen Probes fluxes are similar and the measured fluxes from CXD are typically within a factor of 2 of Van Allen Probes at energies ≲4 MeV. We present data from 17 CXD-equipped GPS satellites covering the 2015 \textquotedblleftSt. Patrick\textquoterights Day\textquotedblright geomagnetic storm to illustrate the scientific applications of such a high data density satellite constellation, and therefore demonstrate that the GPS constellation is positioned to enable new insights in inner magnetospheric physics and space weather forecasting. Morley, Steven; Sullivan, John; Henderson, Michael; Blake, Bernard; Baker, Daniel; Published by: Space Weather Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015SW001339 |
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Energetic electron observations in Earth\textquoterights radiation belts are typically sparse and multi-point studies often rely on serendipitous conjunctions. This paper establishes the scientific utility of the Combined X-ray Dosimeter (CXD), currently flown on 19 satellites in the Global Positioning System (GPS) constellation, by cross-calibrating energetic electron measurements against data from the Van Allen Probes. By breaking our cross-calibration into two parts \textendash one that removes any spectral assumptions from the CXD flux calculation, and one that compares the energy spectra \textendash we first validate the modeled instrument response functions, then the calculated electron fluxes. Unlike previous forward modeling of energetic electron spectra we use a combination of four distributions that, together, capture a wide range of observed spectral shapes. Our two-step approach allowed us to identify, and correct for, small systematic offsets between block IIR and IIF satellites. Using the Magnetic Electron Ion Spectrometer (MagEIS) and Relativistic Electron-Proton Telescope (REPT) on Van Allen Probes as a \textquotedblleftgold standard\textquotedblright we demonstrate that the CXD instruments are well-understood. A robust statistical analysis shows that CXD and Van Allen Probes fluxes are similar and the measured fluxes from CXD are typically within a factor of 2 of Van Allen Probes at energies ≲4 MeV. We present data from 17 CXD-equipped GPS satellites covering the 2015 \textquotedblleftSt. Patrick\textquoterights Day\textquotedblright geomagnetic storm to illustrate the scientific applications of such a high data density satellite constellation, and therefore demonstrate that the GPS constellation is positioned to enable new insights in inner magnetospheric physics and space weather forecasting. Morley, Steven; Sullivan, John; Henderson, Michael; Blake, Bernard; Baker, Daniel; Published by: Space Weather Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015SW001339 |
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Energetic electron observations in Earth\textquoterights radiation belts are typically sparse and multi-point studies often rely on serendipitous conjunctions. This paper establishes the scientific utility of the Combined X-ray Dosimeter (CXD), currently flown on 19 satellites in the Global Positioning System (GPS) constellation, by cross-calibrating energetic electron measurements against data from the Van Allen Probes. By breaking our cross-calibration into two parts \textendash one that removes any spectral assumptions from the CXD flux calculation, and one that compares the energy spectra \textendash we first validate the modeled instrument response functions, then the calculated electron fluxes. Unlike previous forward modeling of energetic electron spectra we use a combination of four distributions that, together, capture a wide range of observed spectral shapes. Our two-step approach allowed us to identify, and correct for, small systematic offsets between block IIR and IIF satellites. Using the Magnetic Electron Ion Spectrometer (MagEIS) and Relativistic Electron-Proton Telescope (REPT) on Van Allen Probes as a \textquotedblleftgold standard\textquotedblright we demonstrate that the CXD instruments are well-understood. A robust statistical analysis shows that CXD and Van Allen Probes fluxes are similar and the measured fluxes from CXD are typically within a factor of 2 of Van Allen Probes at energies ≲4 MeV. We present data from 17 CXD-equipped GPS satellites covering the 2015 \textquotedblleftSt. Patrick\textquoterights Day\textquotedblright geomagnetic storm to illustrate the scientific applications of such a high data density satellite constellation, and therefore demonstrate that the GPS constellation is positioned to enable new insights in inner magnetospheric physics and space weather forecasting. Morley, Steven; Sullivan, John; Henderson, Michael; Blake, Bernard; Baker, Daniel; Published by: Space Weather Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015SW001339 |
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Energetic electron observations in Earth\textquoterights radiation belts are typically sparse and multi-point studies often rely on serendipitous conjunctions. This paper establishes the scientific utility of the Combined X-ray Dosimeter (CXD), currently flown on 19 satellites in the Global Positioning System (GPS) constellation, by cross-calibrating energetic electron measurements against data from the Van Allen Probes. By breaking our cross-calibration into two parts \textendash one that removes any spectral assumptions from the CXD flux calculation, and one that compares the energy spectra \textendash we first validate the modeled instrument response functions, then the calculated electron fluxes. Unlike previous forward modeling of energetic electron spectra we use a combination of four distributions that, together, capture a wide range of observed spectral shapes. Our two-step approach allowed us to identify, and correct for, small systematic offsets between block IIR and IIF satellites. Using the Magnetic Electron Ion Spectrometer (MagEIS) and Relativistic Electron-Proton Telescope (REPT) on Van Allen Probes as a \textquotedblleftgold standard\textquotedblright we demonstrate that the CXD instruments are well-understood. A robust statistical analysis shows that CXD and Van Allen Probes fluxes are similar and the measured fluxes from CXD are typically within a factor of 2 of Van Allen Probes at energies ≲4 MeV. We present data from 17 CXD-equipped GPS satellites covering the 2015 \textquotedblleftSt. Patrick\textquoterights Day\textquotedblright geomagnetic storm to illustrate the scientific applications of such a high data density satellite constellation, and therefore demonstrate that the GPS constellation is positioned to enable new insights in inner magnetospheric physics and space weather forecasting. Morley, Steven; Sullivan, John; Henderson, Michael; Blake, Bernard; Baker, Daniel; Published by: Space Weather Published on: 02/2016 YEAR: 2016 DOI: 10.1002/2015SW001339 |