scholarly journals Statistically measuring the amount of pitch angle scattering that energetic electrons undergo as they drift across the plasmaspheric drainage plume at geosynchronous orbit

2014 ◽  
Vol 119 (3) ◽  
pp. 1814-1826 ◽  
Author(s):  
Joseph E. Borovsky ◽  
Reiner H. W. Friedel ◽  
Michael H. Denton
2014 ◽  
Vol 32 (5) ◽  
pp. 507-518 ◽  
Author(s):  
S. S. Chang ◽  
B. B. Ni ◽  
J. Bortnik ◽  
C. Zhou ◽  
Z. Y. Zhao ◽  
...  

Abstract. Modulated high-frequency (HF) heating of the ionosphere provides a feasible means of artificially generating extremely low-frequency (ELF)/very low-frequency (VLF) whistler waves, which can leak into the inner magnetosphere and contribute to resonant interactions with high-energy electrons in the plasmasphere. By ray tracing the magnetospheric propagation of ELF/VLF emissions artificially generated at low-invariant latitudes, we evaluate the relativistic electron resonant energies along the ray paths and show that propagating artificial ELF/VLF waves can resonate with electrons from ~ 100 keV to ~ 10 MeV. We further implement test particle simulations to investigate the effects of resonant scattering of energetic electrons due to triggered monotonic/single-frequency ELF/VLF waves. The results indicate that within the period of a resonance timescale, changes in electron pitch angle and kinetic energy are stochastic, and the overall effect is cumulative, that is, the changes averaged over all test electrons increase monotonically with time. The localized rates of wave-induced pitch-angle scattering and momentum diffusion in the plasmasphere are analyzed in detail for artificially generated ELF/VLF whistlers with an observable in situ amplitude of ~ 10 pT. While the local momentum diffusion of relativistic electrons is small, with a rate of < 10−7 s−1, the local pitch-angle scattering can be intense near the loss cone with a rate of ~ 10−4 s−1. Our investigation further supports the feasibility of artificial triggering of ELF/VLF whistler waves for removal of high-energy electrons at lower L shells within the plasmasphere. Moreover, our test particle simulation results show quantitatively good agreement with quasi-linear diffusion coefficients, confirming the applicability of both methods to evaluate the resonant diffusion effect of artificial generated ELF/VLF whistlers.


2001 ◽  
Vol 203 ◽  
pp. 577-579
Author(s):  
M. Vandas

Spacecraft measurements of energetic electrons in the vicinity of the Earth's bow shock and interplanetary shocks are analyzed and compared with theoretical calculations. It is concluded that shock drift acceleration of electrons is very modified by an additional process, probably by strong pitch angle scattering. Calculations including this effect are presented.


2012 ◽  
Vol 8 (S294) ◽  
pp. 153-154
Author(s):  
Jing Huang

AbstractFrom the observations of radio and HXR bursts, the escape rate of energetic electrons trapped in the flare loops is studied based on the trap-plus-precipitation model for the kinematics of energetic electrons in solar flares. Coulomb collision is regarded as the main pitch angle scattering of trapped electrons in the decay phase of the event on 2004 December 1. The escape rate of trapped electrons decreases firstly and then increases, which indicates the evolution of the plasma density in the flare loops during the decay phase.


2018 ◽  
Vol 123 (11) ◽  
pp. 9265-9274 ◽  
Author(s):  
W. W. Eshetu ◽  
J. G. Lyon ◽  
M. K. Hudson ◽  
M. J. Wiltberger

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