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J. B. Blake - One of the best experts on this subject based on the ideXlab platform.
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electron microburst size distribution derived with aerocube 6
Journal of Geophysical Research, 2020Co-Authors: Mykhaylo Shumko, J. B. Blake, T P Obrien, A Johnson, J G Sample, B Griffith, D L Turner, O V Agapitov, S G ClaudepierreAbstract:Microbursts are an impulsive increase of electrons from the radiation belts into the atmosphere and have been directly observed in low Earth orbit and the upper atmosphere. Prior work has estimated that Microbursts are capable of rapidly depleting the radiation belt electrons on the order of a day; hence, their role to radiation belt electron losses must be considered. Losses due to Microbursts are not well constrained, and more work is necessary to accurately quantify their contribution as a loss process. To address this question, we present a statistical study of > 35 keV microburst sizes using the pair of AeroCube-6 CubeSats. The microburst size distribution in low Earth orbit and the magnetic equator was derived using both spacecraft. In low Earth orbit, the majority of Microbursts were observed, while the AeroCube-6 separation was less than a few tens of kilometers, mostly in latitude. To account for the statistical effects of random microburst locations and sizes, Monte Carlo and analytic models were developed to test hypothesized microburst size distributions. A family of microburst size distributions were tested, and a Markov chain Monte Carlo sampler was used to estimate the optimal distribution of model parameters. Finally, a majority of observed Microbursts map to sizes less than 200 km at the magnetic equator. Since Microbursts are widely believed to be generated by scattering of radiation belt electrons by whistler mode waves, the observed microburst size distribution was compared to whistler mode chorus size distributions derived in prior literature.
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Allen Radiation Belts. Space Weather, 10: n/a. doi: 10.1029/2012SW000869 Authors
2012Co-Authors: Harlan E. Spence, J. B. Blake, A B Crew, D M Klumpar, S. Driscoll, Mosleh T. P. O&aposAbstract:Focusing on size and energy dependence of electron Microbursts from the Van Allen radiation belt
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observation of relativistic electron Microbursts in conjunction with intense radiation belt whistler mode waves
Geophysical Research Letters, 2011Co-Authors: K Kersten, M D Looper, J. B. Blake, C A Cattell, A W Breneman, K Goetz, P J Kellogg, J R Wygant, L B Wilson, I RothAbstract:[1] We present multi-satellite observations of large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron Microbursts in near magnetic conjunction with Wind and STEREO. This evidence of microburst precipitation occurring at the same time and at nearly the same magnetic local time and L-shell with a bursty temporal structure similar to that of the observed large amplitude wave packets suggests a causal connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave–particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.
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observation of relativistic electron Microbursts in conjunction with intense radiation belt whistler mode waves
arXiv: Space Physics, 2011Co-Authors: K Kersten, M D Looper, J. B. Blake, C A Cattell, A W Breneman, K Goetz, P J Kellogg, J R Wygant, L B Wilson, I RothAbstract:We present multi-satellite observations indicating a strong correlation between large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron Microbursts in near magnetic conjunction with Wind and STEREO. The microburst precipitation exhibits a bursty temporal structure similar to that of the observed large amplitude wave packets, suggesting a connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave--particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.
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quantification of relativistic electron microburst losses during the gem storms
Geophysical Research Letters, 2004Co-Authors: T P Obrien, M D Looper, J. B. BlakeAbstract:[1] Bursty precipitation of relativistic electrons has been implicated as a major loss process during magnetic storms. One type of precipitation, Microbursts, appears to contain enough electrons to empty the prestorm outer radiation belt in approximately a day. During storms that result in high fluxes of trapped relativistic electrons, Microbursts continue for several days into the recovery phase, when trapped fluxes are dramatically increasing. The present study shows that this apparent inconsistency is resolved by observations that the number of electrons lost through Microbursts is 10–100 times larger during the main phase than during the recovery phase of several magnetic storms chosen by the Geospace Environment Modeling (GEM) program.
Yoshizumi Miyoshi - One of the best experts on this subject based on the ideXlab platform.
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relativistic electron Microbursts as high energy tail of pulsating aurora electrons
Geophysical Research Letters, 2020Co-Authors: Yoshizumi Miyoshi, Shinji Saito, S Kurita, Kazushi Asamura, K Hosokawa, Takeshi Sakanoi, Takefumi Mitani, Yasunobu Ogawa, Shinichiro OyamaAbstract:In this study, by simulating the wave-particle interactions, we show that sub-relativistic/relativistic electron Microbursts form the high-energy tail of pulsating aurora (PsA). Whistler-mode choru...
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relativistic electron Microbursts and variations in trapped mev electron fluxes during the 8 9 october 2012 storm sampex and van allen probes observations
Geophysical Research Letters, 2016Co-Authors: Satoshi Kurita, Bernard J Blake, Yoshizumi Miyoshi, Geoffery D Reeves, C A KletzingAbstract:It has been suggested that whistler mode chorus is responsible for both acceleration of MeV electrons and relativistic electron Microbursts through resonant wave-particle interactions. Relativistic electron Microbursts have been considered as an important loss mechanism of radiation belt electrons. Here we report on the observations of relativistic electron Microbursts and flux variations of trapped MeV electrons during the 8-9 October 2012 storm, using the SAMPEX and Van Allen Probes satellites. Observations by the satellites show that relativistic electron Microbursts correlate well with the rapid enhancement of trapped MeV electron fluxes by chorus wave-particle interactions, indicating that acceleration by chorus is much more efficient than losses by Microbursts during the storm. It is also revealed that the strong chorus wave activity without relativistic electron Microbursts does not lead to significant flux variations of relativistic electrons. Thus, effective acceleration of relativistic electrons is caused by chorus that can cause relativistic electron Microbursts.
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relativistic electron Microbursts associated with whistler chorus rising tone elements gemsis rbw simulations
Journal of Geophysical Research, 2012Co-Authors: Shinji Saito, Yoshizumi Miyoshi, K SekiAbstract:[1] Relativistic electron Microbursts, which are bursty enhancements of the precipitation of relativistic electrons, are often observed by low-altitude satellite measurements. These Microbursts are likely to play an important role in high-energy electron flux loss in the outer radiation belt. Some observations suggest that whistler chorus waves are a cause of relativistic electron Microbursts. First, we derived the relativistic time of flight model considering the propagation of whistler mode waves, and then investigated characteristics of the precipitations. We found that relativistic electron precipitation has a positive energy dispersion at low altitude. The duration of electron precipitation by one whistler chorus element decreases when the energy of the precipitated electrons is increased. We then performed three-dimensional test particle simulation with a newly developed wave-particle interaction model using realistic plasma parameters in the inner magnetosphere. The test particle simulation showed for the first time that the resonant interactions with whistler chorus elements at high-latitudes produce bursty enhancements of relativistic electron precipitation, thus confirming the results of the TOF analysis. A few Hz modulations are embedded in the precipitating electron flux variations, which is associated with the repetition period of the whistler chorus elements. The simulation results indicate that Microbursts of relativistic electrons of the outer belt are caused by chorus wave-particle interactions at high latitudes and a series of rising tone elements of chorus waves produce a few Hz modulation of Microbursts observed by the SAMPEX satellite.
M D Looper - One of the best experts on this subject based on the ideXlab platform.
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observation of relativistic electron Microbursts in conjunction with intense radiation belt whistler mode waves
Geophysical Research Letters, 2011Co-Authors: K Kersten, M D Looper, J. B. Blake, C A Cattell, A W Breneman, K Goetz, P J Kellogg, J R Wygant, L B Wilson, I RothAbstract:[1] We present multi-satellite observations of large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron Microbursts in near magnetic conjunction with Wind and STEREO. This evidence of microburst precipitation occurring at the same time and at nearly the same magnetic local time and L-shell with a bursty temporal structure similar to that of the observed large amplitude wave packets suggests a causal connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave–particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.
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observation of relativistic electron Microbursts in conjunction with intense radiation belt whistler mode waves
arXiv: Space Physics, 2011Co-Authors: K Kersten, M D Looper, J. B. Blake, C A Cattell, A W Breneman, K Goetz, P J Kellogg, J R Wygant, L B Wilson, I RothAbstract:We present multi-satellite observations indicating a strong correlation between large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron Microbursts in near magnetic conjunction with Wind and STEREO. The microburst precipitation exhibits a bursty temporal structure similar to that of the observed large amplitude wave packets, suggesting a connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave--particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.
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energization of relativistic electrons in the presence of ulf power and mev Microbursts evidence for dual ulf and vlf acceleration
Journal of Geophysical Research, 2003Co-Authors: T P Obrien, M D Looper, J. B. Blake, K R Lorentzen, I R Mann, Nigel P Meredith, J F Fennell, D K MillingAbstract:[1] We examine signatures of two types of waves that may be involved in the acceleration of energetic electrons in Earth's outer radiation belts. We have compiled a database of ULF wave power from SAMNET and IMAGE ground magnetometer stations for 1987–2001. Long-duration, comprehensive, in situ VLF/ELF chorus wave observations are not available, so we infer chorus wave activity from low-altitude SAMPEX observations of MeV electron Microbursts for 1996–2001 since Microbursts are thought to be caused by interactions between chorus and trapped electrons. We compare the ULF and microburst observations to in situ trapped electrons observed by high-altitude satellites from 1989–2001. We find that electron acceleration at low L shells is closely associated with both ULF activity and MeV Microbursts and thereby probably also with chorus activity. Electron flux enhancements across the outer radiation belt are, in general, related to both ULF and VLF/ELF activity. However, we suggest that electron flux peaks observed at L ∼ 4.5 are likely caused by VLF/ELF wave acceleration, while ULF activity probably produces the dominant electron acceleration at geosynchronous orbit and beyond.
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relativistic electron Microbursts during the gem storms
Geophysical Research Letters, 2001Co-Authors: K R Lorentzen, M D Looper, J. B. BlakeAbstract:Observations of relativistic (> 1M eV) electr on Microbursts by the Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX) satellite are frequently asso- ciated with geomagnetic storms. We examine the charac- teristics of these Microbursts during 1997 and 1998, pay- ing particular attention to the three storms selected by the Geospace Environment Modeling (GEM) community for special study: May 15, 1997, September25, 1998, and Octo- ber 19, 1998. The relativistic electron Microbursts strongly correlate with both the Dst and Kp indices and generally increase in intensity and move to lower L shells during the recovery phases of geomagnetic storms. During the recovery phases of the Septemberand October1998 storms, the num- bers of >1 MeV electrons lost from the radiation belts to the microburst precipitation are estimated to be 2.5×10 25 and 3.3×10 24 , respectively. In both cases, the microburst loss is a significant fraction of the total radiation belt population.
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sampex observations of precipitation bursts in the outer radiation belt
Journal of Geophysical Research, 2000Co-Authors: Rumi Nakamura, Yohsuke Kamide, M Isowa, J. B. Blake, D N Baker, M D LooperAbstract:The occurrence frequency of precipitation bursts of > 1 MeV electrons in the outer radiation belt is examined using data from the SAMPEX satellite. Electron burst characteristics shown in this paper include the dependence of the precipitation on magnetic local time, radial distance and geomagnetic activity. Precipitation bursts with timescales < 1 s, i.e., Microbursts, are studied in detail, including their dependence on the phases of geomagnetic storms. It is found that precipitation bursts occur typically in the region between L = 4 and L = 6. Microbursts tend to occur at L lower than the bursts with timescales of several tens of seconds. The number of observed Microbursts significantly increases during storms, appearing mainly in the morning sector early in the recovery phase of storms. These findings suggest that the Microbursts may be due to interactions with electron whistler waves, which take place near the dawnside plasmapause in the density irregularities that are perhaps created in the "recovering" plasmasphere. The prevalence of bursty precipitation indicates that this enhanced loss component of the relativistic electron flux should be taken into account in any quantitative model of relativistic electron acceleration processes.
J R Wygant - One of the best experts on this subject based on the ideXlab platform.
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observations directly linking relativistic electron Microbursts to whistler mode chorus van allen probes and firebird ii
Geophysical Research Letters, 2017Co-Authors: A W Breneman, A Johnson, J G Sample, D L Turner, O V Agapitov, A B Crew, D M Klumpar, M Shumko, O Santolik, J R WygantAbstract:We present observations that provide the strongest evidence yet that discrete whistler mode chorus packets cause relativistic electron Microbursts. On 20 January 2016 near 1944 UT the low Earth orbiting CubeSat Focused Investigations of Relativistic Electron Bursts: Intensity, Range, and Dynamics (FIREBIRD II) observed energetic Microbursts (near L = 5.6 and MLT = 10.5) from its lower limit of 220 keV, to 1 MeV. In the outer radiation belt and magnetically conjugate, Van Allen Probe A observed rising-tone, lower band chorus waves with durations and cadences similar to the Microbursts. No other waves were observed. This is the first time that chorus and Microbursts have been simultaneously observed with a separation smaller than a chorus packet. A majority of the Microbursts do not have the energy dispersion expected for trapped electrons bouncing between mirror points. This confirms that the electrons are rapidly (nonlinearly) scattered into the loss cone by a coherent interaction with the large amplitude (up to ∼900 pT) chorus. Comparison of observed time-averaged microburst flux and estimated total electron drift shell content at L = 5.6 indicate that Microbursts may represent a significant source of energetic electron loss in the outer radiation belt.
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observation of relativistic electron Microbursts in conjunction with intense radiation belt whistler mode waves
Geophysical Research Letters, 2011Co-Authors: K Kersten, M D Looper, J. B. Blake, C A Cattell, A W Breneman, K Goetz, P J Kellogg, J R Wygant, L B Wilson, I RothAbstract:[1] We present multi-satellite observations of large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron Microbursts in near magnetic conjunction with Wind and STEREO. This evidence of microburst precipitation occurring at the same time and at nearly the same magnetic local time and L-shell with a bursty temporal structure similar to that of the observed large amplitude wave packets suggests a causal connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave–particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.
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observation of relativistic electron Microbursts in conjunction with intense radiation belt whistler mode waves
arXiv: Space Physics, 2011Co-Authors: K Kersten, M D Looper, J. B. Blake, C A Cattell, A W Breneman, K Goetz, P J Kellogg, J R Wygant, L B Wilson, I RothAbstract:We present multi-satellite observations indicating a strong correlation between large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron Microbursts in near magnetic conjunction with Wind and STEREO. The microburst precipitation exhibits a bursty temporal structure similar to that of the observed large amplitude wave packets, suggesting a connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave--particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.
A W Breneman - One of the best experts on this subject based on the ideXlab platform.
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observations directly linking relativistic electron Microbursts to whistler mode chorus van allen probes and firebird ii
Geophysical Research Letters, 2017Co-Authors: A W Breneman, A Johnson, J G Sample, D L Turner, O V Agapitov, A B Crew, D M Klumpar, M Shumko, O Santolik, J R WygantAbstract:We present observations that provide the strongest evidence yet that discrete whistler mode chorus packets cause relativistic electron Microbursts. On 20 January 2016 near 1944 UT the low Earth orbiting CubeSat Focused Investigations of Relativistic Electron Bursts: Intensity, Range, and Dynamics (FIREBIRD II) observed energetic Microbursts (near L = 5.6 and MLT = 10.5) from its lower limit of 220 keV, to 1 MeV. In the outer radiation belt and magnetically conjugate, Van Allen Probe A observed rising-tone, lower band chorus waves with durations and cadences similar to the Microbursts. No other waves were observed. This is the first time that chorus and Microbursts have been simultaneously observed with a separation smaller than a chorus packet. A majority of the Microbursts do not have the energy dispersion expected for trapped electrons bouncing between mirror points. This confirms that the electrons are rapidly (nonlinearly) scattered into the loss cone by a coherent interaction with the large amplitude (up to ∼900 pT) chorus. Comparison of observed time-averaged microburst flux and estimated total electron drift shell content at L = 5.6 indicate that Microbursts may represent a significant source of energetic electron loss in the outer radiation belt.
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observation of relativistic electron Microbursts in conjunction with intense radiation belt whistler mode waves
Geophysical Research Letters, 2011Co-Authors: K Kersten, M D Looper, J. B. Blake, C A Cattell, A W Breneman, K Goetz, P J Kellogg, J R Wygant, L B Wilson, I RothAbstract:[1] We present multi-satellite observations of large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron Microbursts in near magnetic conjunction with Wind and STEREO. This evidence of microburst precipitation occurring at the same time and at nearly the same magnetic local time and L-shell with a bursty temporal structure similar to that of the observed large amplitude wave packets suggests a causal connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave–particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.
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observation of relativistic electron Microbursts in conjunction with intense radiation belt whistler mode waves
arXiv: Space Physics, 2011Co-Authors: K Kersten, M D Looper, J. B. Blake, C A Cattell, A W Breneman, K Goetz, P J Kellogg, J R Wygant, L B Wilson, I RothAbstract:We present multi-satellite observations indicating a strong correlation between large amplitude radiation belt whistler-mode waves and relativistic electron precipitation. On separate occasions during the Wind petal orbits and STEREO phasing orbits, Wind and STEREO recorded intense whistler-mode waves in the outer nightside equatorial radiation belt with peak-to-peak amplitudes exceeding 300 mV/m. During these intervals of intense wave activity, SAMPEX recorded relativistic electron Microbursts in near magnetic conjunction with Wind and STEREO. The microburst precipitation exhibits a bursty temporal structure similar to that of the observed large amplitude wave packets, suggesting a connection between the two phenomena. Simulation studies corroborate this idea, showing that nonlinear wave--particle interactions may result in rapid energization and scattering on timescales comparable to those of the impulsive relativistic electron precipitation.