Journal ArticleDOI
Substorm dependence of chorus amplitudes: Implications for the acceleration of electrons to relativistic energies
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In this article, a survey of wave data from the CRRES Plasma Wave Experiment for lower band (0.1-0.5f(ce)) and upper band ( 0.5-1.0f(c)) chorus was presented to assess whether these waves could play an important role in the acceleration of a seed population of electrons to relativistic energies during and following geomagnetic storms.Abstract:
Intense interest currently exists in determining the roles played by various wave-particle interactions in the acceleration of electrons to relativistic energies during/following geomagnetic storms. Here we present a survey of wave data from the CRRES Plasma Wave Experiment for lower band (0.1-0.5f(ce)) and upper band (0.5-1.0f(ce)) chorus, f(ce) being the electron gyrofrequency, to assess whether these waves could play an important role in the acceleration of a seed population of electrons to relativistic energies during and following geomagnetic storms. Outside of the plasmapause the chorus emissions are largely substorm-dependent, and all chorus emissions are enhanced when substorm activity is enhanced. The equatorial chorus (/ lambda (m) / 300 nT) with average amplitudes typically >0.5 mV m(-1) predominantly in the region 3 15 degrees) is strongest in the lower band during active conditions, with average amplitudes typically >0.5 mV m(-1) in the region 3 < L < 7 over a range of local times on the dayside, principally in the range 0600-1500 MLT, Consistent with wave generation in the horns of the magnetosphere. An inner population of weak, substorm-independent emissions with average amplitudes generally < 0.2 mV m(-1) are seen in both bands largely inside L = 4 on the nightside during quiet (AE < 100 nT) and moderate (100 nT < AE < 300 nT) conditions. These emissions lie inside the plasmapause and are attributed to signals from lightning and ground-based VLF transmitters. We conclude that the significant increases in chorus amplitudes seen outside of the plasmapause during substorms support the theory of electron acceleration by whistler mode chorus in that region. The results suggest that electron acceleration by whistle mode chorus during/following geomagnetic storms can only be effective when there are periods of prolonged substorm activity following the main phase of the geomagnetic storm.read more
Citations
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Journal ArticleDOI
Timescale for radiation belt electron acceleration by whistler mode chorus waves
Richard B. Horne,Richard M. Thorne,Sarah A. Glauert,Jay M. Albert,Nigel P. Meredith,Nigel P. Meredith,Roger R. Anderson +6 more
TL;DR: In this paper, the authors present CRRES data on the spatial distribution of chorus emissions during active conditions and calculate the pitch angle and energy diffusion rates in three magnetic local time (MLT) sectors and obtain a timescale for acceleration.
Journal ArticleDOI
Corotating solar wind streams and recurrent geomagnetic activity: A review
Bruce T. Tsurutani,Bruce T. Tsurutani,Walter D. Gonzalez,Alicia L. Clúa de Gonzalez,Fernando L. Guarnieri,Nat Gopalswamy,Manuel Grande,Yohsuke Kamide,Yoshiya Kasahara,Gang Lu,Ian R. Mann,Robert L. McPherron,Finn Søraas,Vytenis M. Vasyliunas +13 more
TL;DR: In this paper, it was shown that geomagnetic storms associated with high-speed streams/CIRs will have the same initial, main, and recovery phases as those associated with ICME-related magnetic storms but that the interplanetary causes are considerably different.
Journal ArticleDOI
Theory and simulation of the generation of whistler-mode chorus
TL;DR: In this article, the authors derived the relativistic second-order resonance condition for a whistler-mode wave with a varying frequency and found that the seeds of chorus emissions with a rising frequency are generated near the magnetic equator as a result of a nonlinear growth mechanism that depends on the wave amplitude.
Journal ArticleDOI
Review of radiation belt relativistic electron losses
Robyn Millan,Richard M. Thorne +1 more
TL;DR: In this article, a brief review of radiation belt electron losses is presented, which are vitally important for controlling the dynamics of the radiation belts and their relative importance to the overall rate of loss.
Journal ArticleDOI
Statistical analysis of relativistic electron energies for cyclotron resonance with EMIC waves observed on CRRES
Nigel P. Meredith,Richard M. Thorne,Richard B. Horne,Danny Summers,Danny Summers,Brian Fraser,Roger R. Anderson +6 more
TL;DR: In this article, a statistical analysis of over 800 EMIC wave events observed on the CRRES spacecraft is performed to establish whether scattering can occur at geophysically interesting energies (less than or equal to 2 MeV).
References
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Journal ArticleDOI
Relativistic theory of wave‐particle resonant diffusion with application to electron acceleration in the magnetosphere
TL;DR: In this paper, a model was proposed to account for the observed variations in the flux and pitch angle distribution of relativistic electrons during geomagnetic storms by combining pitch angle scattering by intense EMIC waves and energy diffusion during cyclotron resonant interaction with whistler mode chorus outside the plasmasphere.
Journal ArticleDOI
An ISEE/Whistler model of equatorial electron density in the magnetosphere
TL;DR: In this paper, an empirical model of equatorial electron density in the magnetosphere covering the L range 2.25-8.9043 was presented for application to the local time interval 00-15 MLT, and a way to extend the model to the 15-24 MLT period is presented.
Journal ArticleDOI
Pitch-angle diffusion of radiation belt electrons within the plasmasphere.
TL;DR: In this paper, the formation of the quiet-time electron slot, which divides the radiation belt electrons into an inner and an outer zone, was investigated. But the results were limited to the inner radiation zone.
Journal ArticleDOI
Postmidnight chorus: A substorm phenomenon
TL;DR: In this paper, the post-midnight chorus was detected in the midnight sector of the magnetosphere in conjunction with magnetospheric substorms and the characteristics of these emissions such as their frequency time structure, emission frequency with respect to the local equatorial electron gyrofrequency, intensity-time variation, and the average intensity were investigated.