Bibliography

Inter-calibrated Measurements of Intense Whistlers by Arase and Van Allen Probes

Abstract Measurements of electromagnetic waves in space plasmas are an important tool for our understanding of physical processes in this environment. Inter-calibration of data from different spacecraft missions is necessary for combining their measurements in empirical models or in case studies. We show results collected during a close conjunction of the Van Allen Probes and Arase spacecraft. The inter-calibration is based on a fortuitous case of common observations of strong whistlers at frequencies between a few hundred hertz and 10 kHz, which are generated by the same lightning strokes and which propagate along very similar paths to the two spacecraft. Measured amplitudes of the magnetic field fluctuations are the same within ∼14\% precision of our analysis, corresponding to 1.2 dB. Currently archived electric field measurements show twice larger amplitudes on Arase compared to Van Allen Probes but they start to match within ∼33\% precision (2.5 dB) once the newest results on the interface of the antennas to the surrounding plasma are included in the calibration procedures. Ray tracing simulations help us to build a consistent scenario of wave propagation to both spacecraft reflected by a successful inter-calibration of the polarization and propagation parameters obtained from multicomponent measurements. We succeed in linking the spacecraft observations to localizations of lightning return strokes by two different ground based networks which independently verify the correctness of the Universal Time tags of waveform measurements by both spacecraft missions, with an uncertainty better than 10 ms. This article is protected by copyright. All rights reserved.

Santolik, O.; Miyoshi, Y.; Kolmašová, I.; Matsuda, S.; Hospodarsky, G.; Hartley, D.; Kasahara, Y.; Kojima, H.; Matsuoka, A.; Shinohara, I.; Kurth, W.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029700

calibration of measeurements of electromagnetic waves; Whistlers; ducts; Van Allen Probes

Inter-calibrated Measurements of Intense Whistlers by Arase and Van Allen Probes

Abstract Measurements of electromagnetic waves in space plasmas are an important tool for our understanding of physical processes in this environment. Inter-calibration of data from different spacecraft missions is necessary for combining their measurements in empirical models or in case studies. We show results collected during a close conjunction of the Van Allen Probes and Arase spacecraft. The inter-calibration is based on a fortuitous case of common observations of strong whistlers at frequencies between a few hundred hertz and 10 kHz, which are generated by the same lightning strokes and which propagate along very similar paths to the two spacecraft. Measured amplitudes of the magnetic field fluctuations are the same within ∼14\% precision of our analysis, corresponding to 1.2 dB. Currently archived electric field measurements show twice larger amplitudes on Arase compared to Van Allen Probes but they start to match within ∼33\% precision (2.5 dB) once the newest results on the interface of the antennas to the surrounding plasma are included in the calibration procedures. Ray tracing simulations help us to build a consistent scenario of wave propagation to both spacecraft reflected by a successful inter-calibration of the polarization and propagation parameters obtained from multicomponent measurements. We succeed in linking the spacecraft observations to localizations of lightning return strokes by two different ground based networks which independently verify the correctness of the Universal Time tags of waveform measurements by both spacecraft missions, with an uncertainty better than 10 ms. This article is protected by copyright. All rights reserved.

Santolik, O.; Miyoshi, Y.; Kolmašová, I.; Matsuda, S.; Hospodarsky, G.; Hartley, D.; Kasahara, Y.; Kojima, H.; Matsuoka, A.; Shinohara, I.; Kurth, W.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029700

calibration of measeurements of electromagnetic waves; Whistlers; ducts; Van Allen Probes

Inter-calibrated Measurements of Intense Whistlers by Arase and Van Allen Probes

Abstract Measurements of electromagnetic waves in space plasmas are an important tool for our understanding of physical processes in this environment. Inter-calibration of data from different spacecraft missions is necessary for combining their measurements in empirical models or in case studies. We show results collected during a close conjunction of the Van Allen Probes and Arase spacecraft. The inter-calibration is based on a fortuitous case of common observations of strong whistlers at frequencies between a few hundred hertz and 10 kHz, which are generated by the same lightning strokes and which propagate along very similar paths to the two spacecraft. Measured amplitudes of the magnetic field fluctuations are the same within ∼14\% precision of our analysis, corresponding to 1.2 dB. Currently archived electric field measurements show twice larger amplitudes on Arase compared to Van Allen Probes but they start to match within ∼33\% precision (2.5 dB) once the newest results on the interface of the antennas to the surrounding plasma are included in the calibration procedures. Ray tracing simulations help us to build a consistent scenario of wave propagation to both spacecraft reflected by a successful inter-calibration of the polarization and propagation parameters obtained from multicomponent measurements. We succeed in linking the spacecraft observations to localizations of lightning return strokes by two different ground based networks which independently verify the correctness of the Universal Time tags of waveform measurements by both spacecraft missions, with an uncertainty better than 10 ms. This article is protected by copyright. All rights reserved.

Santolik, O.; Miyoshi, Y.; Kolmašová, I.; Matsuda, S.; Hospodarsky, G.; Hartley, D.; Kasahara, Y.; Kojima, H.; Matsuoka, A.; Shinohara, I.; Kurth, W.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029700

calibration of measeurements of electromagnetic waves; Whistlers; ducts; Van Allen Probes

Inter-calibrated Measurements of Intense Whistlers by Arase and Van Allen Probes

Abstract Measurements of electromagnetic waves in space plasmas are an important tool for our understanding of physical processes in this environment. Inter-calibration of data from different spacecraft missions is necessary for combining their measurements in empirical models or in case studies. We show results collected during a close conjunction of the Van Allen Probes and Arase spacecraft. The inter-calibration is based on a fortuitous case of common observations of strong whistlers at frequencies between a few hundred hertz and 10 kHz, which are generated by the same lightning strokes and which propagate along very similar paths to the two spacecraft. Measured amplitudes of the magnetic field fluctuations are the same within ∼14\% precision of our analysis, corresponding to 1.2 dB. Currently archived electric field measurements show twice larger amplitudes on Arase compared to Van Allen Probes but they start to match within ∼33\% precision (2.5 dB) once the newest results on the interface of the antennas to the surrounding plasma are included in the calibration procedures. Ray tracing simulations help us to build a consistent scenario of wave propagation to both spacecraft reflected by a successful inter-calibration of the polarization and propagation parameters obtained from multicomponent measurements. We succeed in linking the spacecraft observations to localizations of lightning return strokes by two different ground based networks which independently verify the correctness of the Universal Time tags of waveform measurements by both spacecraft missions, with an uncertainty better than 10 ms. This article is protected by copyright. All rights reserved.

Santolik, O.; Miyoshi, Y.; Kolmašová, I.; Matsuda, S.; Hospodarsky, G.; Hartley, D.; Kasahara, Y.; Kojima, H.; Matsuoka, A.; Shinohara, I.; Kurth, W.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029700

calibration of measeurements of electromagnetic waves; Whistlers; ducts; Van Allen Probes

Inter-calibrated Measurements of Intense Whistlers by Arase and Van Allen Probes

Abstract Measurements of electromagnetic waves in space plasmas are an important tool for our understanding of physical processes in this environment. Inter-calibration of data from different spacecraft missions is necessary for combining their measurements in empirical models or in case studies. We show results collected during a close conjunction of the Van Allen Probes and Arase spacecraft. The inter-calibration is based on a fortuitous case of common observations of strong whistlers at frequencies between a few hundred hertz and 10 kHz, which are generated by the same lightning strokes and which propagate along very similar paths to the two spacecraft. Measured amplitudes of the magnetic field fluctuations are the same within ∼14\% precision of our analysis, corresponding to 1.2 dB. Currently archived electric field measurements show twice larger amplitudes on Arase compared to Van Allen Probes but they start to match within ∼33\% precision (2.5 dB) once the newest results on the interface of the antennas to the surrounding plasma are included in the calibration procedures. Ray tracing simulations help us to build a consistent scenario of wave propagation to both spacecraft reflected by a successful inter-calibration of the polarization and propagation parameters obtained from multicomponent measurements. We succeed in linking the spacecraft observations to localizations of lightning return strokes by two different ground based networks which independently verify the correctness of the Universal Time tags of waveform measurements by both spacecraft missions, with an uncertainty better than 10 ms. This article is protected by copyright. All rights reserved.

Santolik, O.; Miyoshi, Y.; Kolmašová, I.; Matsuda, S.; Hospodarsky, G.; Hartley, D.; Kasahara, Y.; Kojima, H.; Matsuoka, A.; Shinohara, I.; Kurth, W.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029700

calibration of measeurements of electromagnetic waves; Whistlers; ducts; Van Allen Probes

Inter-calibrated Measurements of Intense Whistlers by Arase and Van Allen Probes

Abstract Measurements of electromagnetic waves in space plasmas are an important tool for our understanding of physical processes in this environment. Inter-calibration of data from different spacecraft missions is necessary for combining their measurements in empirical models or in case studies. We show results collected during a close conjunction of the Van Allen Probes and Arase spacecraft. The inter-calibration is based on a fortuitous case of common observations of strong whistlers at frequencies between a few hundred hertz and 10 kHz, which are generated by the same lightning strokes and which propagate along very similar paths to the two spacecraft. Measured amplitudes of the magnetic field fluctuations are the same within ∼14\% precision of our analysis, corresponding to 1.2 dB. Currently archived electric field measurements show twice larger amplitudes on Arase compared to Van Allen Probes but they start to match within ∼33\% precision (2.5 dB) once the newest results on the interface of the antennas to the surrounding plasma are included in the calibration procedures. Ray tracing simulations help us to build a consistent scenario of wave propagation to both spacecraft reflected by a successful inter-calibration of the polarization and propagation parameters obtained from multicomponent measurements. We succeed in linking the spacecraft observations to localizations of lightning return strokes by two different ground based networks which independently verify the correctness of the Universal Time tags of waveform measurements by both spacecraft missions, with an uncertainty better than 10 ms. This article is protected by copyright. All rights reserved.

Santolik, O.; Miyoshi, Y.; Kolmašová, I.; Matsuda, S.; Hospodarsky, G.; Hartley, D.; Kasahara, Y.; Kojima, H.; Matsuoka, A.; Shinohara, I.; Kurth, W.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029700

calibration of measeurements of electromagnetic waves; Whistlers; ducts; Van Allen Probes

Inter-calibrated Measurements of Intense Whistlers by Arase and Van Allen Probes

Abstract Measurements of electromagnetic waves in space plasmas are an important tool for our understanding of physical processes in this environment. Inter-calibration of data from different spacecraft missions is necessary for combining their measurements in empirical models or in case studies. We show results collected during a close conjunction of the Van Allen Probes and Arase spacecraft. The inter-calibration is based on a fortuitous case of common observations of strong whistlers at frequencies between a few hundred hertz and 10 kHz, which are generated by the same lightning strokes and which propagate along very similar paths to the two spacecraft. Measured amplitudes of the magnetic field fluctuations are the same within ∼14\% precision of our analysis, corresponding to 1.2 dB. Currently archived electric field measurements show twice larger amplitudes on Arase compared to Van Allen Probes but they start to match within ∼33\% precision (2.5 dB) once the newest results on the interface of the antennas to the surrounding plasma are included in the calibration procedures. Ray tracing simulations help us to build a consistent scenario of wave propagation to both spacecraft reflected by a successful inter-calibration of the polarization and propagation parameters obtained from multicomponent measurements. We succeed in linking the spacecraft observations to localizations of lightning return strokes by two different ground based networks which independently verify the correctness of the Universal Time tags of waveform measurements by both spacecraft missions, with an uncertainty better than 10 ms. This article is protected by copyright. All rights reserved.

Santolik, O.; Miyoshi, Y.; Kolmašová, I.; Matsuda, S.; Hospodarsky, G.; Hartley, D.; Kasahara, Y.; Kojima, H.; Matsuoka, A.; Shinohara, I.; Kurth, W.; Kletzing, C.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029700

calibration of measeurements of electromagnetic waves; Whistlers; ducts; Van Allen Probes

Can Earth’s magnetotail plasma sheet produce a source of relativistic electrons for the radiation belts?

Abstract Simultaneous observations from Van Allen Probes (RBSP) in Earth’s outer radiation belt (∼4-6 RE) and Magnetospheric Multiscale (MMS) in the magnetotail plasma sheet at >20 RE geocentric distance are used to compare relative levels of relativistic electron phase space density (PSD) for constant values of the first adiabatic invariant, M. We present new evidence from two events showing: i) at times, there is sufficient PSD in the central plasma sheet to provide a source of >1 MeV electrons into the outer belt; ii) the most intense levels of relativistic electrons are not accelerated in the solar wind or transported from the inner magnetosphere and thus must be accelerated rapidly (within ∼minutes or less) and efficiently across a broad region of the magnetotail itself; and iii) the highest intensity relativistic electrons observed by MMS were confined within only the central plasma sheet. The answer to the title question here is: yes, it can, however whether Earth’s plasma sheet actually does provide a source of several 100s keV to >1 MeV electrons to the outer belt and how often it does so remain important outstanding questions.

Turner, Drew; Cohen, Ian; Michael, Adam; Sorathia, Kareem; Merkin, Slava; Mauk, Barry; Ukhorskiy, Sasha; Murphy, Kyle; Gabrielse, Christine; Boyd, Alexander; Fennell, Joseph; Blake, Bernard; Claudepierre, Seth; Drozdov, Alexander; Jaynes, Allison; Ripoll, Jean-Francois; Reeves, Geoffrey;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL095495

Radiation belts; plasma sheet; Particle acceleration; relativistic electrons; inner magnetosphere; magnetotail; Van Allen Probes

Can Earth’s magnetotail plasma sheet produce a source of relativistic electrons for the radiation belts?

Abstract Simultaneous observations from Van Allen Probes (RBSP) in Earth’s outer radiation belt (∼4-6 RE) and Magnetospheric Multiscale (MMS) in the magnetotail plasma sheet at >20 RE geocentric distance are used to compare relative levels of relativistic electron phase space density (PSD) for constant values of the first adiabatic invariant, M. We present new evidence from two events showing: i) at times, there is sufficient PSD in the central plasma sheet to provide a source of >1 MeV electrons into the outer belt; ii) the most intense levels of relativistic electrons are not accelerated in the solar wind or transported from the inner magnetosphere and thus must be accelerated rapidly (within ∼minutes or less) and efficiently across a broad region of the magnetotail itself; and iii) the highest intensity relativistic electrons observed by MMS were confined within only the central plasma sheet. The answer to the title question here is: yes, it can, however whether Earth’s plasma sheet actually does provide a source of several 100s keV to >1 MeV electrons to the outer belt and how often it does so remain important outstanding questions.

Turner, Drew; Cohen, Ian; Michael, Adam; Sorathia, Kareem; Merkin, Slava; Mauk, Barry; Ukhorskiy, Sasha; Murphy, Kyle; Gabrielse, Christine; Boyd, Alexander; Fennell, Joseph; Blake, Bernard; Claudepierre, Seth; Drozdov, Alexander; Jaynes, Allison; Ripoll, Jean-Francois; Reeves, Geoffrey;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL095495

Radiation belts; plasma sheet; Particle acceleration; relativistic electrons; inner magnetosphere; magnetotail; Van Allen Probes

Can Earth’s magnetotail plasma sheet produce a source of relativistic electrons for the radiation belts?

Abstract Simultaneous observations from Van Allen Probes (RBSP) in Earth’s outer radiation belt (∼4-6 RE) and Magnetospheric Multiscale (MMS) in the magnetotail plasma sheet at >20 RE geocentric distance are used to compare relative levels of relativistic electron phase space density (PSD) for constant values of the first adiabatic invariant, M. We present new evidence from two events showing: i) at times, there is sufficient PSD in the central plasma sheet to provide a source of >1 MeV electrons into the outer belt; ii) the most intense levels of relativistic electrons are not accelerated in the solar wind or transported from the inner magnetosphere and thus must be accelerated rapidly (within ∼minutes or less) and efficiently across a broad region of the magnetotail itself; and iii) the highest intensity relativistic electrons observed by MMS were confined within only the central plasma sheet. The answer to the title question here is: yes, it can, however whether Earth’s plasma sheet actually does provide a source of several 100s keV to >1 MeV electrons to the outer belt and how often it does so remain important outstanding questions.

Turner, Drew; Cohen, Ian; Michael, Adam; Sorathia, Kareem; Merkin, Slava; Mauk, Barry; Ukhorskiy, Sasha; Murphy, Kyle; Gabrielse, Christine; Boyd, Alexander; Fennell, Joseph; Blake, Bernard; Claudepierre, Seth; Drozdov, Alexander; Jaynes, Allison; Ripoll, Jean-Francois; Reeves, Geoffrey;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL095495

Radiation belts; plasma sheet; Particle acceleration; relativistic electrons; inner magnetosphere; magnetotail; Van Allen Probes

Can Earth’s magnetotail plasma sheet produce a source of relativistic electrons for the radiation belts?

Abstract Simultaneous observations from Van Allen Probes (RBSP) in Earth’s outer radiation belt (∼4-6 RE) and Magnetospheric Multiscale (MMS) in the magnetotail plasma sheet at >20 RE geocentric distance are used to compare relative levels of relativistic electron phase space density (PSD) for constant values of the first adiabatic invariant, M. We present new evidence from two events showing: i) at times, there is sufficient PSD in the central plasma sheet to provide a source of >1 MeV electrons into the outer belt; ii) the most intense levels of relativistic electrons are not accelerated in the solar wind or transported from the inner magnetosphere and thus must be accelerated rapidly (within ∼minutes or less) and efficiently across a broad region of the magnetotail itself; and iii) the highest intensity relativistic electrons observed by MMS were confined within only the central plasma sheet. The answer to the title question here is: yes, it can, however whether Earth’s plasma sheet actually does provide a source of several 100s keV to >1 MeV electrons to the outer belt and how often it does so remain important outstanding questions.

Turner, Drew; Cohen, Ian; Michael, Adam; Sorathia, Kareem; Merkin, Slava; Mauk, Barry; Ukhorskiy, Sasha; Murphy, Kyle; Gabrielse, Christine; Boyd, Alexander; Fennell, Joseph; Blake, Bernard; Claudepierre, Seth; Drozdov, Alexander; Jaynes, Allison; Ripoll, Jean-Francois; Reeves, Geoffrey;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL095495

Radiation belts; plasma sheet; Particle acceleration; relativistic electrons; inner magnetosphere; magnetotail; Van Allen Probes

Can Earth’s magnetotail plasma sheet produce a source of relativistic electrons for the radiation belts?

Abstract Simultaneous observations from Van Allen Probes (RBSP) in Earth’s outer radiation belt (∼4-6 RE) and Magnetospheric Multiscale (MMS) in the magnetotail plasma sheet at >20 RE geocentric distance are used to compare relative levels of relativistic electron phase space density (PSD) for constant values of the first adiabatic invariant, M. We present new evidence from two events showing: i) at times, there is sufficient PSD in the central plasma sheet to provide a source of >1 MeV electrons into the outer belt; ii) the most intense levels of relativistic electrons are not accelerated in the solar wind or transported from the inner magnetosphere and thus must be accelerated rapidly (within ∼minutes or less) and efficiently across a broad region of the magnetotail itself; and iii) the highest intensity relativistic electrons observed by MMS were confined within only the central plasma sheet. The answer to the title question here is: yes, it can, however whether Earth’s plasma sheet actually does provide a source of several 100s keV to >1 MeV electrons to the outer belt and how often it does so remain important outstanding questions.

Turner, Drew; Cohen, Ian; Michael, Adam; Sorathia, Kareem; Merkin, Slava; Mauk, Barry; Ukhorskiy, Sasha; Murphy, Kyle; Gabrielse, Christine; Boyd, Alexander; Fennell, Joseph; Blake, Bernard; Claudepierre, Seth; Drozdov, Alexander; Jaynes, Allison; Ripoll, Jean-Francois; Reeves, Geoffrey;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL095495

Radiation belts; plasma sheet; Particle acceleration; relativistic electrons; inner magnetosphere; magnetotail; Van Allen Probes

Can Earth’s magnetotail plasma sheet produce a source of relativistic electrons for the radiation belts?

Abstract Simultaneous observations from Van Allen Probes (RBSP) in Earth’s outer radiation belt (∼4-6 RE) and Magnetospheric Multiscale (MMS) in the magnetotail plasma sheet at >20 RE geocentric distance are used to compare relative levels of relativistic electron phase space density (PSD) for constant values of the first adiabatic invariant, M. We present new evidence from two events showing: i) at times, there is sufficient PSD in the central plasma sheet to provide a source of >1 MeV electrons into the outer belt; ii) the most intense levels of relativistic electrons are not accelerated in the solar wind or transported from the inner magnetosphere and thus must be accelerated rapidly (within ∼minutes or less) and efficiently across a broad region of the magnetotail itself; and iii) the highest intensity relativistic electrons observed by MMS were confined within only the central plasma sheet. The answer to the title question here is: yes, it can, however whether Earth’s plasma sheet actually does provide a source of several 100s keV to >1 MeV electrons to the outer belt and how often it does so remain important outstanding questions.

Turner, Drew; Cohen, Ian; Michael, Adam; Sorathia, Kareem; Merkin, Slava; Mauk, Barry; Ukhorskiy, Sasha; Murphy, Kyle; Gabrielse, Christine; Boyd, Alexander; Fennell, Joseph; Blake, Bernard; Claudepierre, Seth; Drozdov, Alexander; Jaynes, Allison; Ripoll, Jean-Francois; Reeves, Geoffrey;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL095495

Radiation belts; plasma sheet; Particle acceleration; relativistic electrons; inner magnetosphere; magnetotail; Van Allen Probes

A statistical analysis of duration and frequency chirping rate of falling tone chorus

AbstractThe duration (τ) and chirping rate (Γ) of whistler mode chorus waves are two of the most important properties to understand chorus generation mechanism and to quantify effects of nonlinear wave particle interactions on radiation belt electron acceleration. In this study, we perform the first statistical analysis of the duration and chirping rate of falling tone chorus elements using Van Allen Probes data.We found that τ increases and Γ decreases with increasing L-shell, although the dependence is weak. The duration from dawnside and dayside have similar distributions, which is a bit longer than those from duskside and nightside. However, Γ has little dependence on MLT. The relation between τ and Γ shows that τ scales with Γ as , supporting one of the previous theoretical models of rising tone chorus in Teng et al.(2017). Our results should provide important insights to deepen our understanding of falling tone chorus excitation.

Xie, Yi; Teng, Shangchun; Wu, Yifan; Tao, Xin;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL095349

chorus waves; falling tone; Frequency chirping; Van Allen Probes

Simultaneous pulsating aurora and microburst observations with ground-based fast auroral imagers and CubeSat FIREBIRD-II

Abstract We report on the relationship between a pulsating aurora and a relativistic electron microburst using simultaneous observations of ground-based fast auroral imagers with the FIREBIRD-� � CubeSat for the first time. We conducted a detailed analysis of an event on October 8, 2018 and found that the occurrence of the pulsating aurora with internal modulations corresponds to the flux enhancement of electrons with energy ranging from ∼220 keV to >1 MeV detected with Flight Unit 4, one of FIREBIRD’s CubeSat, with a time delay of ∼585 ms. Combining of this time delay result and time of flight model, we suggest that the theory the pulsating aurora and the microburst occur due to the chorus waves at different latitudes along the same field-line by Miyoshi et al. (2020).

Kawamura, Miki; Sakanoi, Takeshi; Fukizawa, Mizuki; Miyoshi, Yoshizumi; Hosokawa, Keisuke; Tsuchiya, Fuminori; Katoh, Yuto; Ogawa, Yasunobu; Asamura, Kazushi; Saito, Shinji; Spence, Harlan; Johnson, Arlo; Oyama, Shin’ichiro; Brändström, Urban;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL094494

pulsating aurora; Microbursts; chorus waves; Van Allen Probes

Simultaneous pulsating aurora and microburst observations with ground-based fast auroral imagers and CubeSat FIREBIRD-II

Abstract We report on the relationship between a pulsating aurora and a relativistic electron microburst using simultaneous observations of ground-based fast auroral imagers with the FIREBIRD-� � CubeSat for the first time. We conducted a detailed analysis of an event on October 8, 2018 and found that the occurrence of the pulsating aurora with internal modulations corresponds to the flux enhancement of electrons with energy ranging from ∼220 keV to >1 MeV detected with Flight Unit 4, one of FIREBIRD’s CubeSat, with a time delay of ∼585 ms. Combining of this time delay result and time of flight model, we suggest that the theory the pulsating aurora and the microburst occur due to the chorus waves at different latitudes along the same field-line by Miyoshi et al. (2020).

Kawamura, Miki; Sakanoi, Takeshi; Fukizawa, Mizuki; Miyoshi, Yoshizumi; Hosokawa, Keisuke; Tsuchiya, Fuminori; Katoh, Yuto; Ogawa, Yasunobu; Asamura, Kazushi; Saito, Shinji; Spence, Harlan; Johnson, Arlo; Oyama, Shin’ichiro; Brändström, Urban;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL094494

pulsating aurora; Microbursts; chorus waves; Van Allen Probes

Simultaneous pulsating aurora and microburst observations with ground-based fast auroral imagers and CubeSat FIREBIRD-II

Abstract We report on the relationship between a pulsating aurora and a relativistic electron microburst using simultaneous observations of ground-based fast auroral imagers with the FIREBIRD-� � CubeSat for the first time. We conducted a detailed analysis of an event on October 8, 2018 and found that the occurrence of the pulsating aurora with internal modulations corresponds to the flux enhancement of electrons with energy ranging from ∼220 keV to >1 MeV detected with Flight Unit 4, one of FIREBIRD’s CubeSat, with a time delay of ∼585 ms. Combining of this time delay result and time of flight model, we suggest that the theory the pulsating aurora and the microburst occur due to the chorus waves at different latitudes along the same field-line by Miyoshi et al. (2020).

Kawamura, Miki; Sakanoi, Takeshi; Fukizawa, Mizuki; Miyoshi, Yoshizumi; Hosokawa, Keisuke; Tsuchiya, Fuminori; Katoh, Yuto; Ogawa, Yasunobu; Asamura, Kazushi; Saito, Shinji; Spence, Harlan; Johnson, Arlo; Oyama, Shin’ichiro; Brändström, Urban;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL094494

pulsating aurora; Microbursts; chorus waves; Van Allen Probes

Simultaneous pulsating aurora and microburst observations with ground-based fast auroral imagers and CubeSat FIREBIRD-II

Abstract We report on the relationship between a pulsating aurora and a relativistic electron microburst using simultaneous observations of ground-based fast auroral imagers with the FIREBIRD-� � CubeSat for the first time. We conducted a detailed analysis of an event on October 8, 2018 and found that the occurrence of the pulsating aurora with internal modulations corresponds to the flux enhancement of electrons with energy ranging from ∼220 keV to >1 MeV detected with Flight Unit 4, one of FIREBIRD’s CubeSat, with a time delay of ∼585 ms. Combining of this time delay result and time of flight model, we suggest that the theory the pulsating aurora and the microburst occur due to the chorus waves at different latitudes along the same field-line by Miyoshi et al. (2020).

Kawamura, Miki; Sakanoi, Takeshi; Fukizawa, Mizuki; Miyoshi, Yoshizumi; Hosokawa, Keisuke; Tsuchiya, Fuminori; Katoh, Yuto; Ogawa, Yasunobu; Asamura, Kazushi; Saito, Shinji; Spence, Harlan; Johnson, Arlo; Oyama, Shin’ichiro; Brändström, Urban;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL094494

pulsating aurora; Microbursts; chorus waves; Van Allen Probes

Simultaneous pulsating aurora and microburst observations with ground-based fast auroral imagers and CubeSat FIREBIRD-II

Abstract We report on the relationship between a pulsating aurora and a relativistic electron microburst using simultaneous observations of ground-based fast auroral imagers with the FIREBIRD-� � CubeSat for the first time. We conducted a detailed analysis of an event on October 8, 2018 and found that the occurrence of the pulsating aurora with internal modulations corresponds to the flux enhancement of electrons with energy ranging from ∼220 keV to >1 MeV detected with Flight Unit 4, one of FIREBIRD’s CubeSat, with a time delay of ∼585 ms. Combining of this time delay result and time of flight model, we suggest that the theory the pulsating aurora and the microburst occur due to the chorus waves at different latitudes along the same field-line by Miyoshi et al. (2020).

Kawamura, Miki; Sakanoi, Takeshi; Fukizawa, Mizuki; Miyoshi, Yoshizumi; Hosokawa, Keisuke; Tsuchiya, Fuminori; Katoh, Yuto; Ogawa, Yasunobu; Asamura, Kazushi; Saito, Shinji; Spence, Harlan; Johnson, Arlo; Oyama, Shin’ichiro; Brändström, Urban;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL094494

pulsating aurora; Microbursts; chorus waves; Van Allen Probes

Simultaneous pulsating aurora and microburst observations with ground-based fast auroral imagers and CubeSat FIREBIRD-II

Abstract We report on the relationship between a pulsating aurora and a relativistic electron microburst using simultaneous observations of ground-based fast auroral imagers with the FIREBIRD-� � CubeSat for the first time. We conducted a detailed analysis of an event on October 8, 2018 and found that the occurrence of the pulsating aurora with internal modulations corresponds to the flux enhancement of electrons with energy ranging from ∼220 keV to >1 MeV detected with Flight Unit 4, one of FIREBIRD’s CubeSat, with a time delay of ∼585 ms. Combining of this time delay result and time of flight model, we suggest that the theory the pulsating aurora and the microburst occur due to the chorus waves at different latitudes along the same field-line by Miyoshi et al. (2020).

Kawamura, Miki; Sakanoi, Takeshi; Fukizawa, Mizuki; Miyoshi, Yoshizumi; Hosokawa, Keisuke; Tsuchiya, Fuminori; Katoh, Yuto; Ogawa, Yasunobu; Asamura, Kazushi; Saito, Shinji; Spence, Harlan; Johnson, Arlo; Oyama, Shin’ichiro; Brändström, Urban;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL094494

pulsating aurora; Microbursts; chorus waves; Van Allen Probes

Simultaneous pulsating aurora and microburst observations with ground-based fast auroral imagers and CubeSat FIREBIRD-II

Abstract We report on the relationship between a pulsating aurora and a relativistic electron microburst using simultaneous observations of ground-based fast auroral imagers with the FIREBIRD-� � CubeSat for the first time. We conducted a detailed analysis of an event on October 8, 2018 and found that the occurrence of the pulsating aurora with internal modulations corresponds to the flux enhancement of electrons with energy ranging from ∼220 keV to >1 MeV detected with Flight Unit 4, one of FIREBIRD’s CubeSat, with a time delay of ∼585 ms. Combining of this time delay result and time of flight model, we suggest that the theory the pulsating aurora and the microburst occur due to the chorus waves at different latitudes along the same field-line by Miyoshi et al. (2020).

Kawamura, Miki; Sakanoi, Takeshi; Fukizawa, Mizuki; Miyoshi, Yoshizumi; Hosokawa, Keisuke; Tsuchiya, Fuminori; Katoh, Yuto; Ogawa, Yasunobu; Asamura, Kazushi; Saito, Shinji; Spence, Harlan; Johnson, Arlo; Oyama, Shin’ichiro; Brändström, Urban;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL094494

pulsating aurora; Microbursts; chorus waves; Van Allen Probes

Simultaneous pulsating aurora and microburst observations with ground-based fast auroral imagers and CubeSat FIREBIRD-II

Abstract We report on the relationship between a pulsating aurora and a relativistic electron microburst using simultaneous observations of ground-based fast auroral imagers with the FIREBIRD-� � CubeSat for the first time. We conducted a detailed analysis of an event on October 8, 2018 and found that the occurrence of the pulsating aurora with internal modulations corresponds to the flux enhancement of electrons with energy ranging from ∼220 keV to >1 MeV detected with Flight Unit 4, one of FIREBIRD’s CubeSat, with a time delay of ∼585 ms. Combining of this time delay result and time of flight model, we suggest that the theory the pulsating aurora and the microburst occur due to the chorus waves at different latitudes along the same field-line by Miyoshi et al. (2020).

Kawamura, Miki; Sakanoi, Takeshi; Fukizawa, Mizuki; Miyoshi, Yoshizumi; Hosokawa, Keisuke; Tsuchiya, Fuminori; Katoh, Yuto; Ogawa, Yasunobu; Asamura, Kazushi; Saito, Shinji; Spence, Harlan; Johnson, Arlo; Oyama, Shin’ichiro; Brändström, Urban;

Published by: Geophysical Research Letters      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL094494

pulsating aurora; Microbursts; chorus waves; Van Allen Probes

Field-Aligned Electron Density Distribution of the Inner Magnetosphere Inferred from Coordinated Observations of Arase and Van Allen Probes

Plain Language Summary The plasmasphere is the region filled with cold, dense ionized gas in geospace. The ionized gas mainly consists in protons, helium ions, oxygen ions and electrons, which come from Earth’s ionosphere and fill in magnetic flux tubes. The density distribution of the ionized gas along the flux tube provides important information to understand how the ions and electrons have been supplied from the ionosphere. Many satellites fly in the equatorial plane, hence, do not provide information on the electron density along the field. The RBSP and the Arase satellites have different inclinations and sometimes they simultaneously fly near the equator and off the equator on the same magnetic field line. Using electron densities observed by these satellites during the 7 Sep 2017 storm, we successfully estimated the electron density distribution along of the field lines inside the partially refilled plasmasphere, outside of the plasmasphere and in the tail-like structure called a plume.

Obana, Yuki; Miyashita, Yukinaga; Maruyama, Naomi; Shinbori, Atsuki; Nosé, Masahito; Shoji, Masafumi; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Kasahara, Yoshiya; Miyoshi, Yoshizumi; Shinohara, Iku; Kurth, William; Smith, Charles; MacDowall, Robert;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029073

plasmasphere; inner magnetosphere; Arase satellite; Van Allen Probes satellite; simultaneous observation; Geomagnetic storm; Van Allen Probes

Field-Aligned Electron Density Distribution of the Inner Magnetosphere Inferred from Coordinated Observations of Arase and Van Allen Probes

Plain Language Summary The plasmasphere is the region filled with cold, dense ionized gas in geospace. The ionized gas mainly consists in protons, helium ions, oxygen ions and electrons, which come from Earth’s ionosphere and fill in magnetic flux tubes. The density distribution of the ionized gas along the flux tube provides important information to understand how the ions and electrons have been supplied from the ionosphere. Many satellites fly in the equatorial plane, hence, do not provide information on the electron density along the field. The RBSP and the Arase satellites have different inclinations and sometimes they simultaneously fly near the equator and off the equator on the same magnetic field line. Using electron densities observed by these satellites during the 7 Sep 2017 storm, we successfully estimated the electron density distribution along of the field lines inside the partially refilled plasmasphere, outside of the plasmasphere and in the tail-like structure called a plume.

Obana, Yuki; Miyashita, Yukinaga; Maruyama, Naomi; Shinbori, Atsuki; Nosé, Masahito; Shoji, Masafumi; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Kasahara, Yoshiya; Miyoshi, Yoshizumi; Shinohara, Iku; Kurth, William; Smith, Charles; MacDowall, Robert;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029073

plasmasphere; inner magnetosphere; Arase satellite; Van Allen Probes satellite; simultaneous observation; Geomagnetic storm; Van Allen Probes

Field-Aligned Electron Density Distribution of the Inner Magnetosphere Inferred from Coordinated Observations of Arase and Van Allen Probes

Plain Language Summary The plasmasphere is the region filled with cold, dense ionized gas in geospace. The ionized gas mainly consists in protons, helium ions, oxygen ions and electrons, which come from Earth’s ionosphere and fill in magnetic flux tubes. The density distribution of the ionized gas along the flux tube provides important information to understand how the ions and electrons have been supplied from the ionosphere. Many satellites fly in the equatorial plane, hence, do not provide information on the electron density along the field. The RBSP and the Arase satellites have different inclinations and sometimes they simultaneously fly near the equator and off the equator on the same magnetic field line. Using electron densities observed by these satellites during the 7 Sep 2017 storm, we successfully estimated the electron density distribution along of the field lines inside the partially refilled plasmasphere, outside of the plasmasphere and in the tail-like structure called a plume.

Obana, Yuki; Miyashita, Yukinaga; Maruyama, Naomi; Shinbori, Atsuki; Nosé, Masahito; Shoji, Masafumi; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Kasahara, Yoshiya; Miyoshi, Yoshizumi; Shinohara, Iku; Kurth, William; Smith, Charles; MacDowall, Robert;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029073

plasmasphere; inner magnetosphere; Arase satellite; Van Allen Probes satellite; simultaneous observation; Geomagnetic storm; Van Allen Probes

Field-Aligned Electron Density Distribution of the Inner Magnetosphere Inferred from Coordinated Observations of Arase and Van Allen Probes

Plain Language Summary The plasmasphere is the region filled with cold, dense ionized gas in geospace. The ionized gas mainly consists in protons, helium ions, oxygen ions and electrons, which come from Earth’s ionosphere and fill in magnetic flux tubes. The density distribution of the ionized gas along the flux tube provides important information to understand how the ions and electrons have been supplied from the ionosphere. Many satellites fly in the equatorial plane, hence, do not provide information on the electron density along the field. The RBSP and the Arase satellites have different inclinations and sometimes they simultaneously fly near the equator and off the equator on the same magnetic field line. Using electron densities observed by these satellites during the 7 Sep 2017 storm, we successfully estimated the electron density distribution along of the field lines inside the partially refilled plasmasphere, outside of the plasmasphere and in the tail-like structure called a plume.

Obana, Yuki; Miyashita, Yukinaga; Maruyama, Naomi; Shinbori, Atsuki; Nosé, Masahito; Shoji, Masafumi; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Kasahara, Yoshiya; Miyoshi, Yoshizumi; Shinohara, Iku; Kurth, William; Smith, Charles; MacDowall, Robert;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029073

plasmasphere; inner magnetosphere; Arase satellite; Van Allen Probes satellite; simultaneous observation; Geomagnetic storm; Van Allen Probes

Field-Aligned Electron Density Distribution of the Inner Magnetosphere Inferred from Coordinated Observations of Arase and Van Allen Probes

Plain Language Summary The plasmasphere is the region filled with cold, dense ionized gas in geospace. The ionized gas mainly consists in protons, helium ions, oxygen ions and electrons, which come from Earth’s ionosphere and fill in magnetic flux tubes. The density distribution of the ionized gas along the flux tube provides important information to understand how the ions and electrons have been supplied from the ionosphere. Many satellites fly in the equatorial plane, hence, do not provide information on the electron density along the field. The RBSP and the Arase satellites have different inclinations and sometimes they simultaneously fly near the equator and off the equator on the same magnetic field line. Using electron densities observed by these satellites during the 7 Sep 2017 storm, we successfully estimated the electron density distribution along of the field lines inside the partially refilled plasmasphere, outside of the plasmasphere and in the tail-like structure called a plume.

Obana, Yuki; Miyashita, Yukinaga; Maruyama, Naomi; Shinbori, Atsuki; Nosé, Masahito; Shoji, Masafumi; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Kasahara, Yoshiya; Miyoshi, Yoshizumi; Shinohara, Iku; Kurth, William; Smith, Charles; MacDowall, Robert;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029073

plasmasphere; inner magnetosphere; Arase satellite; Van Allen Probes satellite; simultaneous observation; Geomagnetic storm; Van Allen Probes

Field-Aligned Electron Density Distribution of the Inner Magnetosphere Inferred from Coordinated Observations of Arase and Van Allen Probes

Plain Language Summary The plasmasphere is the region filled with cold, dense ionized gas in geospace. The ionized gas mainly consists in protons, helium ions, oxygen ions and electrons, which come from Earth’s ionosphere and fill in magnetic flux tubes. The density distribution of the ionized gas along the flux tube provides important information to understand how the ions and electrons have been supplied from the ionosphere. Many satellites fly in the equatorial plane, hence, do not provide information on the electron density along the field. The RBSP and the Arase satellites have different inclinations and sometimes they simultaneously fly near the equator and off the equator on the same magnetic field line. Using electron densities observed by these satellites during the 7 Sep 2017 storm, we successfully estimated the electron density distribution along of the field lines inside the partially refilled plasmasphere, outside of the plasmasphere and in the tail-like structure called a plume.

Obana, Yuki; Miyashita, Yukinaga; Maruyama, Naomi; Shinbori, Atsuki; Nosé, Masahito; Shoji, Masafumi; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Kasahara, Yoshiya; Miyoshi, Yoshizumi; Shinohara, Iku; Kurth, William; Smith, Charles; MacDowall, Robert;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029073

plasmasphere; inner magnetosphere; Arase satellite; Van Allen Probes satellite; simultaneous observation; Geomagnetic storm; Van Allen Probes

Field-Aligned Electron Density Distribution of the Inner Magnetosphere Inferred from Coordinated Observations of Arase and Van Allen Probes

Plain Language Summary The plasmasphere is the region filled with cold, dense ionized gas in geospace. The ionized gas mainly consists in protons, helium ions, oxygen ions and electrons, which come from Earth’s ionosphere and fill in magnetic flux tubes. The density distribution of the ionized gas along the flux tube provides important information to understand how the ions and electrons have been supplied from the ionosphere. Many satellites fly in the equatorial plane, hence, do not provide information on the electron density along the field. The RBSP and the Arase satellites have different inclinations and sometimes they simultaneously fly near the equator and off the equator on the same magnetic field line. Using electron densities observed by these satellites during the 7 Sep 2017 storm, we successfully estimated the electron density distribution along of the field lines inside the partially refilled plasmasphere, outside of the plasmasphere and in the tail-like structure called a plume.

Obana, Yuki; Miyashita, Yukinaga; Maruyama, Naomi; Shinbori, Atsuki; Nosé, Masahito; Shoji, Masafumi; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Kasahara, Yoshiya; Miyoshi, Yoshizumi; Shinohara, Iku; Kurth, William; Smith, Charles; MacDowall, Robert;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029073

plasmasphere; inner magnetosphere; Arase satellite; Van Allen Probes satellite; simultaneous observation; Geomagnetic storm; Van Allen Probes

Field-Aligned Electron Density Distribution of the Inner Magnetosphere Inferred from Coordinated Observations of Arase and Van Allen Probes

Plain Language Summary The plasmasphere is the region filled with cold, dense ionized gas in geospace. The ionized gas mainly consists in protons, helium ions, oxygen ions and electrons, which come from Earth’s ionosphere and fill in magnetic flux tubes. The density distribution of the ionized gas along the flux tube provides important information to understand how the ions and electrons have been supplied from the ionosphere. Many satellites fly in the equatorial plane, hence, do not provide information on the electron density along the field. The RBSP and the Arase satellites have different inclinations and sometimes they simultaneously fly near the equator and off the equator on the same magnetic field line. Using electron densities observed by these satellites during the 7 Sep 2017 storm, we successfully estimated the electron density distribution along of the field lines inside the partially refilled plasmasphere, outside of the plasmasphere and in the tail-like structure called a plume.

Obana, Yuki; Miyashita, Yukinaga; Maruyama, Naomi; Shinbori, Atsuki; Nosé, Masahito; Shoji, Masafumi; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Kasahara, Yoshiya; Miyoshi, Yoshizumi; Shinohara, Iku; Kurth, William; Smith, Charles; MacDowall, Robert;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029073

plasmasphere; inner magnetosphere; Arase satellite; Van Allen Probes satellite; simultaneous observation; Geomagnetic storm; Van Allen Probes

Field-Aligned Electron Density Distribution of the Inner Magnetosphere Inferred from Coordinated Observations of Arase and Van Allen Probes

Plain Language Summary The plasmasphere is the region filled with cold, dense ionized gas in geospace. The ionized gas mainly consists in protons, helium ions, oxygen ions and electrons, which come from Earth’s ionosphere and fill in magnetic flux tubes. The density distribution of the ionized gas along the flux tube provides important information to understand how the ions and electrons have been supplied from the ionosphere. Many satellites fly in the equatorial plane, hence, do not provide information on the electron density along the field. The RBSP and the Arase satellites have different inclinations and sometimes they simultaneously fly near the equator and off the equator on the same magnetic field line. Using electron densities observed by these satellites during the 7 Sep 2017 storm, we successfully estimated the electron density distribution along of the field lines inside the partially refilled plasmasphere, outside of the plasmasphere and in the tail-like structure called a plume.

Obana, Yuki; Miyashita, Yukinaga; Maruyama, Naomi; Shinbori, Atsuki; Nosé, Masahito; Shoji, Masafumi; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Kasahara, Yoshiya; Miyoshi, Yoshizumi; Shinohara, Iku; Kurth, William; Smith, Charles; MacDowall, Robert;

Published by: Journal of Geophysical Research: Space Physics      Published on: 09/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020JA029073

plasmasphere; inner magnetosphere; Arase satellite; Van Allen Probes satellite; simultaneous observation; Geomagnetic storm; Van Allen Probes

Electromagnetic characteristics of fast magnetosonic waves in the inner magnetosphere

Abstract In evaluating the effects of fast magnetosonic (MS) waves on magnetospheric particles, their magnetic spectra are often obtained from satellite observations, while electric field components are usually derived under the cold plasma approximation. However, such an approximation has not been verified with in situ observations yet. In this paper, we report the electromagnetic characteristic for MS waves in various plasma environments with observations of the Van Allen Probe A. It is found that a considerable number of observed MS waves consist of dominated electrostatic components, which also suggest the importance of inspecting the estimation algorithm for the electric field components. Moreover, the comparison between results from statistical and theoretical analysis shows that electromagnetic characteristics of the observed MS waves can be well predicted by cold plasma theory. Our result indicates the validation of cold plasma approximation to estimate the electric field components of MS waves from their magnetic counterparts in the inner magnetosphere.

Yu, Xiongdong; Yuan, Zhigang; Yao, Fei; Ouyang, Zhihai; Wang, Dedong;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029759

Fast Magnetosonic Waves; Electromagnetic characteristics; Van Allen Probes; Cold plasma approximation

Electromagnetic characteristics of fast magnetosonic waves in the inner magnetosphere

Abstract In evaluating the effects of fast magnetosonic (MS) waves on magnetospheric particles, their magnetic spectra are often obtained from satellite observations, while electric field components are usually derived under the cold plasma approximation. However, such an approximation has not been verified with in situ observations yet. In this paper, we report the electromagnetic characteristic for MS waves in various plasma environments with observations of the Van Allen Probe A. It is found that a considerable number of observed MS waves consist of dominated electrostatic components, which also suggest the importance of inspecting the estimation algorithm for the electric field components. Moreover, the comparison between results from statistical and theoretical analysis shows that electromagnetic characteristics of the observed MS waves can be well predicted by cold plasma theory. Our result indicates the validation of cold plasma approximation to estimate the electric field components of MS waves from their magnetic counterparts in the inner magnetosphere.

Yu, Xiongdong; Yuan, Zhigang; Yao, Fei; Ouyang, Zhihai; Wang, Dedong;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029759

Fast Magnetosonic Waves; Electromagnetic characteristics; Van Allen Probes; Cold plasma approximation

Realistic electron diffusion rates and lifetimes due to scattering by electron holes

AbstractPlasma sheet electron precipitation into the diffuse aurora is critical for magnetosphere-ionosphere coupling. Recent studies have shown that electron phase space holes can pitch-angle scatter electrons and may produce plasma sheet electron precipitation. These studies have assumed identical electron hole parameters to estimate electron scattering rates (Vasko et al., 2018). In this study, we have re-evaluated the efficiency of this scattering by incorporating realistic electron hole properties from direct spacecraft observations into computing electron diffusion rates and lifetimes. The most important electron hole properties in this evaluation are their distributions in velocity and spatial scale and electric field root-mean-square intensity (). Using direct measurements of electron holes during a plasma injection event observed by the Van Allen Probe at , we find that when 4 mV/m electron lifetimes can drop below one hour and are mostly within strong diffusion limits at energies below 10 keV. During an injection observed by the THEMIS spacecraft at , electron holes with even typical intensities (1 mV/m) can deplete low-energy (a few keV) plasma sheet electrons within tens of minutes following injections and convection from the tail. Our results confirm that electron holes are a significant contributor to plasma sheet electron precipitation during injections.

Shen, Yangyang; Vasko, Ivan; Artemyev, Anton; Malaspina, David; Chu, Xiangning; Angelopoulos, Vassilis; Zhang, Xiao-Jia;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029380

diffuse aurora; electron pitch-angle scattering; electron phase space hole; Wave-particle interaction; electron lifetimes; broadband electrostatic fluctuations; Van Allen Probes

Realistic electron diffusion rates and lifetimes due to scattering by electron holes

AbstractPlasma sheet electron precipitation into the diffuse aurora is critical for magnetosphere-ionosphere coupling. Recent studies have shown that electron phase space holes can pitch-angle scatter electrons and may produce plasma sheet electron precipitation. These studies have assumed identical electron hole parameters to estimate electron scattering rates (Vasko et al., 2018). In this study, we have re-evaluated the efficiency of this scattering by incorporating realistic electron hole properties from direct spacecraft observations into computing electron diffusion rates and lifetimes. The most important electron hole properties in this evaluation are their distributions in velocity and spatial scale and electric field root-mean-square intensity (). Using direct measurements of electron holes during a plasma injection event observed by the Van Allen Probe at , we find that when 4 mV/m electron lifetimes can drop below one hour and are mostly within strong diffusion limits at energies below 10 keV. During an injection observed by the THEMIS spacecraft at , electron holes with even typical intensities (1 mV/m) can deplete low-energy (a few keV) plasma sheet electrons within tens of minutes following injections and convection from the tail. Our results confirm that electron holes are a significant contributor to plasma sheet electron precipitation during injections.

Shen, Yangyang; Vasko, Ivan; Artemyev, Anton; Malaspina, David; Chu, Xiangning; Angelopoulos, Vassilis; Zhang, Xiao-Jia;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029380

diffuse aurora; electron pitch-angle scattering; electron phase space hole; Wave-particle interaction; electron lifetimes; broadband electrostatic fluctuations; Van Allen Probes

Trapping and amplification of unguided mode EMIC waves in the radiation belt

AbstractElectromagnetic ion cyclotron (EMIC) waves can cause the scattering loss of the relativistic electrons in the radiation belt. They can be classified into the guided mode and the unguided mode, according to waves propagation behavior. The guided mode waves have been widely investigated in the radiation belt, but the observation of the unguided mode waves have not been expected. Based on the observations of Van Allen Probes, we demonstrate for the first time the existence of the intense unguided L-mode EMIC waves in the radiation belt according to the polarization characteristics. Growth rate analyses indicate that the hot protons with energies of a few hundred keV may provide the free energy for wave growth. The reflection interface formed by the spatial locations of local helium cutoff frequencies can be nearly parallel to the equatorial plane when the proton abundance ratio decreases sharply with -shell. This structure combined with hot protons may lead to the trapping and significant amplification of the unguided mode waves. These results may help to understand the nature of EMIC waves and their dynamics in the radiation belt.

Wang, Geng; Gao, Zhonglei; Wu, MingYu; Wang, GuoQiang; Xiao, SuDong; Chen, YuanQiang; Zou, Zhengyang; Zhang, TieLong;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029322

EMIC waves; unguided mode; Radiation belt; ion abundance ratios; Wave trapping; growth rate; Van Allen Probes

Trapping and amplification of unguided mode EMIC waves in the radiation belt

AbstractElectromagnetic ion cyclotron (EMIC) waves can cause the scattering loss of the relativistic electrons in the radiation belt. They can be classified into the guided mode and the unguided mode, according to waves propagation behavior. The guided mode waves have been widely investigated in the radiation belt, but the observation of the unguided mode waves have not been expected. Based on the observations of Van Allen Probes, we demonstrate for the first time the existence of the intense unguided L-mode EMIC waves in the radiation belt according to the polarization characteristics. Growth rate analyses indicate that the hot protons with energies of a few hundred keV may provide the free energy for wave growth. The reflection interface formed by the spatial locations of local helium cutoff frequencies can be nearly parallel to the equatorial plane when the proton abundance ratio decreases sharply with -shell. This structure combined with hot protons may lead to the trapping and significant amplification of the unguided mode waves. These results may help to understand the nature of EMIC waves and their dynamics in the radiation belt.

Wang, Geng; Gao, Zhonglei; Wu, MingYu; Wang, GuoQiang; Xiao, SuDong; Chen, YuanQiang; Zou, Zhengyang; Zhang, TieLong;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029322

EMIC waves; unguided mode; Radiation belt; ion abundance ratios; Wave trapping; growth rate; Van Allen Probes

Trapping and amplification of unguided mode EMIC waves in the radiation belt

AbstractElectromagnetic ion cyclotron (EMIC) waves can cause the scattering loss of the relativistic electrons in the radiation belt. They can be classified into the guided mode and the unguided mode, according to waves propagation behavior. The guided mode waves have been widely investigated in the radiation belt, but the observation of the unguided mode waves have not been expected. Based on the observations of Van Allen Probes, we demonstrate for the first time the existence of the intense unguided L-mode EMIC waves in the radiation belt according to the polarization characteristics. Growth rate analyses indicate that the hot protons with energies of a few hundred keV may provide the free energy for wave growth. The reflection interface formed by the spatial locations of local helium cutoff frequencies can be nearly parallel to the equatorial plane when the proton abundance ratio decreases sharply with -shell. This structure combined with hot protons may lead to the trapping and significant amplification of the unguided mode waves. These results may help to understand the nature of EMIC waves and their dynamics in the radiation belt.

Wang, Geng; Gao, Zhonglei; Wu, MingYu; Wang, GuoQiang; Xiao, SuDong; Chen, YuanQiang; Zou, Zhengyang; Zhang, TieLong;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029322

EMIC waves; unguided mode; Radiation belt; ion abundance ratios; Wave trapping; growth rate; Van Allen Probes

Simultaneous observations and combined effects of electromagnetic ion cyclotron waves and magnetosonic waves

Abstract Magnetosonic (MS) waves and Electromagnetic ion cyclotron (EMIC) waves are important plasma waves in the magnetosphere. Using the Van Allen Probes observations from 2012 to 2017, we constructed the global distribution of simultaneous occurrence of MS and EMIC waves. We found a total of 214 events, and the waves distribute from the noon sector to the duskside. Furthermore, we quantitatively analyze the combined effects of both waves on protons and electrons by calculating of particle diffusion coefficients and 2-D Fokker-Planck diffusion simulations. The simulation results show the combined effects of MS and EMIC waves. High-frequency EMIC waves and intense MS waves at low proton harmonics are essential for the enhanced proton acceleration at several hundred eV and enhanced electron loss at several MeV. Our results provide new sights into understanding the distribution of MS and EMIC waves and evaluating their combined effects on the evolution of energetic particles.

Teng, S.; Ma, Q.; Tao, X.;

Published by: Geophysical Research Letters      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021GL093885

EMIC waves; MS waves; Wave-particle interaction; diffusion coefficients; Van Allen Probes

Reconstructing the dynamics of the outer electron radiation belt by means of the standard and ensemble Kalman filter with the VERB-3D code

Abstract Reconstruction and prediction of the state of the near-Earth space environment is important for anomaly analysis, development of empirical models and understanding of physical processes. Accurate reanalysis or predictions that account for uncertainties in the associated model and the observations, can be obtained by means of data assimilation. The ensemble Kalman filter (EnKF) is one of the most promising filtering tools for non-linear and high dimensional systems in the context of terrestrial weather prediction. In this study, we adapt traditional ensemble based filtering methods to perform data assimilation in the radiation belts. By performing a fraternal twin experiment, we assess the convergence of the EnKF to the standard Kalman filter (KF). Furthermore, with the split-operator technique, we develop two new three-dimensional EnKF approaches for electron phase space density that account for radial and local processes, and allow for reconstruction of the full 3D radiation belt space. The capabilities and properties of the proposed filter approximations are verified using Van Allen Probe and GOES data. Additionally, we validate the two 3D split-operator Ensemble Kalman filters against the 3D split-operator KF. We show how the use of the split-operator technique allows us to include more physical processes in our simulations and offers computationally efficient data assimilation tools that deliver accurate approximations to the optimal solution of the KF and are suitable for real-time forecasting. Future applications of the EnKF to direct assimilation of fluxes and non-linear estimation of electron lifetimes are discussed.

Tibocha, A.; de Wiljes, J.; Shprits, Y; Aseev, N.;

Published by: Space Weather      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2020SW002672

Kalman Filter; Ensemble Kalman filter; forecasting; Van Allen Probes

The Scalable Plasma Ion Composition and Electron Density (SPICED) model for Earth’s inner magnetosphere

Abstract The plasma mass loading of the terrestrial equatorial inner magnetosphere is a key determinant of the characteristics and propagation of ULF waves. Electron number density is also an important factor for other types of waves such as chorus, hiss and EMIC waves. In this paper, we use Van Allen Probe data from September 2012 to February 2019 to create average models of electron densities and average ion mass in the plasmasphere and plasmatrough, near the Earth’s magnetic equator. These models are combined to provide an estimate of the most probable plasma mass density in the equatorial region. We then use machine learning to form a set of models which are parameterized by the SuperMAG ring current index (SMR) based on the design of the average models. The resulting set of models are capable of predicting the average ion mass, electron density and plasma mass density in the range and over all MLT sectors during a range of conditions where nT. This article is protected by copyright. All rights reserved.

James, Matthew; Yeoman, Tim; Jones, Petra; Sandhu, Jasmine; Goldstein, Jerry;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029565

Van Allen Probes

The Scalable Plasma Ion Composition and Electron Density (SPICED) model for Earth’s inner magnetosphere

Abstract The plasma mass loading of the terrestrial equatorial inner magnetosphere is a key determinant of the characteristics and propagation of ULF waves. Electron number density is also an important factor for other types of waves such as chorus, hiss and EMIC waves. In this paper, we use Van Allen Probe data from September 2012 to February 2019 to create average models of electron densities and average ion mass in the plasmasphere and plasmatrough, near the Earth’s magnetic equator. These models are combined to provide an estimate of the most probable plasma mass density in the equatorial region. We then use machine learning to form a set of models which are parameterized by the SuperMAG ring current index (SMR) based on the design of the average models. The resulting set of models are capable of predicting the average ion mass, electron density and plasma mass density in the range and over all MLT sectors during a range of conditions where nT. This article is protected by copyright. All rights reserved.

James, Matthew; Yeoman, Tim; Jones, Petra; Sandhu, Jasmine; Goldstein, Jerry;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029565

Van Allen Probes

The Scalable Plasma Ion Composition and Electron Density (SPICED) model for Earth’s inner magnetosphere

Abstract The plasma mass loading of the terrestrial equatorial inner magnetosphere is a key determinant of the characteristics and propagation of ULF waves. Electron number density is also an important factor for other types of waves such as chorus, hiss and EMIC waves. In this paper, we use Van Allen Probe data from September 2012 to February 2019 to create average models of electron densities and average ion mass in the plasmasphere and plasmatrough, near the Earth’s magnetic equator. These models are combined to provide an estimate of the most probable plasma mass density in the equatorial region. We then use machine learning to form a set of models which are parameterized by the SuperMAG ring current index (SMR) based on the design of the average models. The resulting set of models are capable of predicting the average ion mass, electron density and plasma mass density in the range and over all MLT sectors during a range of conditions where nT. This article is protected by copyright. All rights reserved.

James, Matthew; Yeoman, Tim; Jones, Petra; Sandhu, Jasmine; Goldstein, Jerry;

Published by: Journal of Geophysical Research: Space Physics      Published on: 08/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029565

Van Allen Probes

Global Survey of Electron Precipitation due to Hiss Waves in the Earth s Plasmasphere and Plumes

Abstract We present a global survey of energetic electron precipitation from the equatorial magnetosphere due to hiss waves in the plasmasphere and plumes. Using Van Allen Probes measurements, we calculate the pitch angle diffusion coefficients at the bounce loss cone, and evaluate the energy spectrum of precipitating electron flux. Our ∼6.5-year survey shows that, during disturbed times, hiss inside the plasmasphere primarily causes the electron precipitation at L > 4 over 8 h < MLT < 18 h, and hiss waves in plumes cause the precipitation at L > 5 over 8 h < MLT < 14 h and L > 4 over 14 h < MLT < 20 h. The precipitating energy flux increases with increasing geomagnetic activity, and is typically higher in the plasmaspheric plume than the plasmasphere. The characteristic energy of precipitation increases from ∼20 keV at L = 6 to ∼100 keV at L = 3, potentially causing the loss of electrons at several hundred keV.

Ma, Q.; Li, W.; Zhang, X.-J.; Bortnik, J.; Shen, X.-C.; Connor, H.; Boyd, A.; Kurth, W.; Hospodarsky, G.; Claudepierre, S.; Reeves, G.; Spence, H.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029644

electron precipitation; hiss wave; plasmasphere; plasmaspheric plume; Precipitating Energy Flux; Van Allen Probes Survey; Van Allen Probes

Global Survey of Electron Precipitation due to Hiss Waves in the Earth s Plasmasphere and Plumes

Abstract We present a global survey of energetic electron precipitation from the equatorial magnetosphere due to hiss waves in the plasmasphere and plumes. Using Van Allen Probes measurements, we calculate the pitch angle diffusion coefficients at the bounce loss cone, and evaluate the energy spectrum of precipitating electron flux. Our ∼6.5-year survey shows that, during disturbed times, hiss inside the plasmasphere primarily causes the electron precipitation at L > 4 over 8 h < MLT < 18 h, and hiss waves in plumes cause the precipitation at L > 5 over 8 h < MLT < 14 h and L > 4 over 14 h < MLT < 20 h. The precipitating energy flux increases with increasing geomagnetic activity, and is typically higher in the plasmaspheric plume than the plasmasphere. The characteristic energy of precipitation increases from ∼20 keV at L = 6 to ∼100 keV at L = 3, potentially causing the loss of electrons at several hundred keV.

Ma, Q.; Li, W.; Zhang, X.-J.; Bortnik, J.; Shen, X.-C.; Connor, H.; Boyd, A.; Kurth, W.; Hospodarsky, G.; Claudepierre, S.; Reeves, G.; Spence, H.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029644

electron precipitation; hiss wave; plasmasphere; plasmaspheric plume; Precipitating Energy Flux; Van Allen Probes Survey; Van Allen Probes

Global Survey of Electron Precipitation due to Hiss Waves in the Earth s Plasmasphere and Plumes

Abstract We present a global survey of energetic electron precipitation from the equatorial magnetosphere due to hiss waves in the plasmasphere and plumes. Using Van Allen Probes measurements, we calculate the pitch angle diffusion coefficients at the bounce loss cone, and evaluate the energy spectrum of precipitating electron flux. Our ∼6.5-year survey shows that, during disturbed times, hiss inside the plasmasphere primarily causes the electron precipitation at L > 4 over 8 h < MLT < 18 h, and hiss waves in plumes cause the precipitation at L > 5 over 8 h < MLT < 14 h and L > 4 over 14 h < MLT < 20 h. The precipitating energy flux increases with increasing geomagnetic activity, and is typically higher in the plasmaspheric plume than the plasmasphere. The characteristic energy of precipitation increases from ∼20 keV at L = 6 to ∼100 keV at L = 3, potentially causing the loss of electrons at several hundred keV.

Ma, Q.; Li, W.; Zhang, X.-J.; Bortnik, J.; Shen, X.-C.; Connor, H.; Boyd, A.; Kurth, W.; Hospodarsky, G.; Claudepierre, S.; Reeves, G.; Spence, H.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029644

electron precipitation; hiss wave; plasmasphere; plasmaspheric plume; Precipitating Energy Flux; Van Allen Probes Survey; Van Allen Probes

Global Survey of Electron Precipitation due to Hiss Waves in the Earth s Plasmasphere and Plumes

Abstract We present a global survey of energetic electron precipitation from the equatorial magnetosphere due to hiss waves in the plasmasphere and plumes. Using Van Allen Probes measurements, we calculate the pitch angle diffusion coefficients at the bounce loss cone, and evaluate the energy spectrum of precipitating electron flux. Our ∼6.5-year survey shows that, during disturbed times, hiss inside the plasmasphere primarily causes the electron precipitation at L > 4 over 8 h < MLT < 18 h, and hiss waves in plumes cause the precipitation at L > 5 over 8 h < MLT < 14 h and L > 4 over 14 h < MLT < 20 h. The precipitating energy flux increases with increasing geomagnetic activity, and is typically higher in the plasmaspheric plume than the plasmasphere. The characteristic energy of precipitation increases from ∼20 keV at L = 6 to ∼100 keV at L = 3, potentially causing the loss of electrons at several hundred keV.

Ma, Q.; Li, W.; Zhang, X.-J.; Bortnik, J.; Shen, X.-C.; Connor, H.; Boyd, A.; Kurth, W.; Hospodarsky, G.; Claudepierre, S.; Reeves, G.; Spence, H.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029644

electron precipitation; hiss wave; plasmasphere; plasmaspheric plume; Precipitating Energy Flux; Van Allen Probes Survey; Van Allen Probes

Superposed Epoch Analysis of Dispersionless Particle Injections Inside Geosynchronous Orbit

AbstractDispersionless injections, involving sudden, simultaneous flux enhancements of energetic particles over some broad range of energy, are a characteristic signature of the particles that are experiencing a significant acceleration and/or rapid inward transport at the leading edge of injections. We have statistically analyzed data from Van Allen Probes (also known as RBSP ) to reveal where the proton (H+) and electron (e–) dispersionless injections occur preferentially inside geosynchronous orbit and how they develop depending on local magnetic field changes. By surveying measurements of RBSP during four tail seasons in 2012–2019, we have identified 171 dispersionless injection events. Most of the events, which are accompanied by local magnetic dipolarizations, occur in the dusk-to-midnight sector, regardless of particle species. Out of the selected 171 events, 75 events exhibit dispersionless injections of both H+ and e–, which occur within 2 minutes of each other. With only three exceptions, the both-species injection events are further divided into two main subgroups: One is the H+ preceding e– events with a time offset of tens of seconds between H+ and e–, and the other the concurrent H+ and e– events without any time offset. Our superposed epoch results raise the intriguing possibility that the presence or absence of a pronounced negative dip in the local magnetic field ahead of the concurrent sharp dipolarization determines which of the two subgroups will occur. The difference between the two subgroups may be explained in terms of the dawn-dusk asymmetry of localized diamagnetic perturbations ahead of a deeply-penetrating dipolarization front.This article is protected by copyright. All rights reserved.

Motoba, T.; Ohtani, S.; Gkioulidou, M.; Ukhorskiy, A; Lanzerotti, L.; Claudepierre, S.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029546

Dispersionless injections; substorms; inner magnetosphere; Van Allen Probes

Superposed Epoch Analysis of Dispersionless Particle Injections Inside Geosynchronous Orbit

AbstractDispersionless injections, involving sudden, simultaneous flux enhancements of energetic particles over some broad range of energy, are a characteristic signature of the particles that are experiencing a significant acceleration and/or rapid inward transport at the leading edge of injections. We have statistically analyzed data from Van Allen Probes (also known as RBSP ) to reveal where the proton (H+) and electron (e–) dispersionless injections occur preferentially inside geosynchronous orbit and how they develop depending on local magnetic field changes. By surveying measurements of RBSP during four tail seasons in 2012–2019, we have identified 171 dispersionless injection events. Most of the events, which are accompanied by local magnetic dipolarizations, occur in the dusk-to-midnight sector, regardless of particle species. Out of the selected 171 events, 75 events exhibit dispersionless injections of both H+ and e–, which occur within 2 minutes of each other. With only three exceptions, the both-species injection events are further divided into two main subgroups: One is the H+ preceding e– events with a time offset of tens of seconds between H+ and e–, and the other the concurrent H+ and e– events without any time offset. Our superposed epoch results raise the intriguing possibility that the presence or absence of a pronounced negative dip in the local magnetic field ahead of the concurrent sharp dipolarization determines which of the two subgroups will occur. The difference between the two subgroups may be explained in terms of the dawn-dusk asymmetry of localized diamagnetic perturbations ahead of a deeply-penetrating dipolarization front.This article is protected by copyright. All rights reserved.

Motoba, T.; Ohtani, S.; Gkioulidou, M.; Ukhorskiy, A; Lanzerotti, L.; Claudepierre, S.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029546

Dispersionless injections; substorms; inner magnetosphere; Van Allen Probes

Superposed Epoch Analysis of Dispersionless Particle Injections Inside Geosynchronous Orbit

AbstractDispersionless injections, involving sudden, simultaneous flux enhancements of energetic particles over some broad range of energy, are a characteristic signature of the particles that are experiencing a significant acceleration and/or rapid inward transport at the leading edge of injections. We have statistically analyzed data from Van Allen Probes (also known as RBSP ) to reveal where the proton (H+) and electron (e–) dispersionless injections occur preferentially inside geosynchronous orbit and how they develop depending on local magnetic field changes. By surveying measurements of RBSP during four tail seasons in 2012–2019, we have identified 171 dispersionless injection events. Most of the events, which are accompanied by local magnetic dipolarizations, occur in the dusk-to-midnight sector, regardless of particle species. Out of the selected 171 events, 75 events exhibit dispersionless injections of both H+ and e–, which occur within 2 minutes of each other. With only three exceptions, the both-species injection events are further divided into two main subgroups: One is the H+ preceding e– events with a time offset of tens of seconds between H+ and e–, and the other the concurrent H+ and e– events without any time offset. Our superposed epoch results raise the intriguing possibility that the presence or absence of a pronounced negative dip in the local magnetic field ahead of the concurrent sharp dipolarization determines which of the two subgroups will occur. The difference between the two subgroups may be explained in terms of the dawn-dusk asymmetry of localized diamagnetic perturbations ahead of a deeply-penetrating dipolarization front.This article is protected by copyright. All rights reserved.

Motoba, T.; Ohtani, S.; Gkioulidou, M.; Ukhorskiy, A; Lanzerotti, L.; Claudepierre, S.;

Published by: Journal of Geophysical Research: Space Physics      Published on: 07/2021

YEAR: 2021     DOI: https://doi.org/10.1029/2021JA029546

Dispersionless injections; substorms; inner magnetosphere; Van Allen Probes