High-frequency thermal fluctuations and instabilities in the radiation belt environment

TitleHigh-frequency thermal fluctuations and instabilities in the radiation belt environment
Publication TypeJournal Article
Year of Publication2018
AuthorsHwang, J, Yoon, PH
JournalJournal of Geophysical Research: Space Physics
Date Published10/2018
Keywordsloss cone instability; Radiation belt; spontaneous emission; upper hybrid wave; Van Allen Probes
AbstractThis paper overviews the electrostatic and electromagnetic theories of spontaneous emission in magnetized plasma as they relate to measured electric and magnetic field fluctuations in quiet time radiation belt and ring current region. The pervasively detected high‐frequency fluctuations in the upper‐hybrid frequency range as well as the background low‐frequency range spectral profile in the whistler mode range are explained within the context of the spontaneous emission theory. The quasilinear calculation of loss‐cone instability is also carried out in order to validate the assumption of spontaneous emission model. It is shown that the saturated wave amplitudes associated with the upper‐hybrid and multiple‐harmonic cyclotron instability are quite low, indicating that the theoretical explanation based upon the assumption of spontaneous emission theory may be adequate for understanding the observed background fluctuations during quiet times.
Short TitleJ. Geophys. Res. Space Physics

Page Last Modified: November 1, 2018