Relativistic theory of wave‐particle resonant diffusion with application to electron acceleration in the magnetosphere
TLDR
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.Abstract:
Resonant diffusion curves for electron cyclotron resonance with field-aligned electromagnetic R mode and L mode electromagnetic ion cyclotron (EMIC) waves are constructed using a fully relativistic treatment. Analytical solutions are derived for the case of a single-ion plasma, and a numerical scheme is developed for the more realistic case of a multi-ion plasma. Diffusion curves are presented, for plasma parameters representative of the Earth's magnetosphere at locations both inside and outside the plasmapause. The results obtained indicate minimal electron energy change along the diffusion curves for resonant interaction with L mode waves. Intense storm time EMIC waves are therefore ineffective for electron stochastic acceleration, although these waves could induce rapid pitch angle scattering for ≳ 1 MeV electrons near the duskside plasmapause. In contrast, significant energy change can occur along the diffusion curves for interaction between resonant electrons and whistler (R mode) waves. The energy change is most pronounced in regions of low plasma density. This suggests that whistler mode waves could provide a viable mechanism for electron acceleration from energies near 100 keV to above 1 MeV in the region outside the plasmapause during the recovery phase of geomagnetic storms. A model is 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.read more
Citations
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The Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on RBSP
Craig Kletzing,William S. Kurth,Mario H. Acuña,Robert J. MacDowall,Roy B. Torbert,T. F. Averkamp,D. Bodet,Scott R. Bounds,M. Chutter,John E. P. Connerney,D. Crawford,J. S. Dolan,R. T. Dvorsky,George Hospodarsky,J. Howard,Vania K. Jordanova,R. A. Johnson,D. L. Kirchner,B. T. Mokrzycki,G. Needell,J. Odom,D. Mark,R. F. Pfaff,J. R. Phillips,Chris Piker,S. L. Remington,Douglas E. Rowland,Ondrej Santolik,R. Schnurr,D. Sheppard,Charles W. Smith,Richard M. Thorne,J. Tyler +32 more
TL;DR: The Electric and Magnetic Field Instrument and Integrated Science (EMFISIS) investigation on the NASA Radiation Belt Storm Probes (now named the Van Allen Probes) mission provides key wave and very low frequency magnetic field measurements to understand radiation belt acceleration, loss, and transport.
Journal ArticleDOI
Science Objectives and Rationale for the Radiation Belt Storm Probes Mission
TL;DR: The NASA Radiation Belt Storm Probes (RBSP) mission as discussed by the authors uses two spacecraft making in situ measurements for at least 2 years in nearly the same highly elliptical, low inclination orbits (1.1×5.8 RE, 10∘).
Journal ArticleDOI
Relativistic electron pitch-angle scattering by electromagnetic ion cyclotron waves during geomagnetic storms
Danny Summers,Richard M. Thorne +1 more
TL;DR: In this article, the authors examined the mechanism of electron pitch-angle diffusion by gyroresonant interaction with EMIC waves as a cause of relativistic electron precipitation loss from the outer radiation belt.
Journal ArticleDOI
Rapid local acceleration of relativistic radiation-belt electrons by magnetospheric chorus
Richard M. Thorne,Wen Li,Binbin Ni,Qianli Ma,Jacob Bortnik,Lunjin Chen,Daniel N. Baker,Harlan E. Spence,Geoffrey D. Reeves,Michael G. Henderson,Craig Kletzing,William S. Kurth,George Hospodarsky,J. B. Blake,Joseph F. Fennell,Seth G. Claudepierre,Shrikanth Kanekal +16 more
TL;DR: High-resolution electron observations obtained during the 9 October storm are reported and chorus scattering explains the temporal evolution of both the energy and angular distribution of the observed relativistic electron flux increase, and detailed modelling demonstrates the remarkable efficiency of wave acceleration in the Earth's outer radiation belt.
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.
References
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