Bibliography

Investigating Loss of Relativistic Electrons Associated With EMIC Waves at Low L Values on 22 June 2015

In this study, rapid loss of relativistic radiation belt electrons at low L* values (2.4\textendash3.2) during a strong geomagnetic storm on 22 June 2015 is investigated along with five possible loss mechanisms. Both the particle and wave data are obtained from the Van Allen Probes. Duskside H+ band electromagnetic ion cyclotron (EMIC) waves were observed during a rapid decrease of relativistic electrons with energy above 5.2 MeV occurring outside the plasmasphere during extreme magnetopause compression. Lower He+ composition and enriched O+ composition are found compared to typical values assumed in other studies of cyclotron resonant scattering of relativistic electrons by EMIC waves. Quantitative analysis demonstrates that even with the existence of He+ band EMIC waves, it is the H+ band EMIC waves that are likely to cause the depletion at small pitch angles and strong gradients in pitch angle distributions of relativistic electrons with energy above 5.2 MeV at low L values for this event. Very low frequency wave activity at other magnetic local time can be favorable for the loss of relativistic electrons at higher pitch angles. An illustrative calculation that combines the nominal pitch angle scattering rate due to whistler mode chorus at high pitch angles with the H+ band EMIC wave loss rate at low pitch angles produces loss on time scale observed at L=2.4\textendash3.2. At high L values and lower energies, radial loss to the magnetopause is a viable explanation.

Qin, Murong; Hudson, Mary; Li, Zhao; Millan, Robyn; Shen, Xiaochen; Shprits, Yuri; Woodger, Leslie; Jaynes, Allison; Kletzing, Craig;

Published by: Journal of Geophysical Research: Space Physics      Published on: 05/2019

YEAR: 2019     DOI: 10.1029/2018JA025726

cold ion composition; EMIC wave; minimum resonant energy; pitch angle diffusion; quasi-linear theory; relativistic electron loss; Van Allen Probes

Investigation of EMIC wave scattering as the cause for the BARREL January 17, 2013 relativistic electron precipitation event: a quantitative comparison of simulation with observations

Electromagnetic ion cyclotron (EMIC) waves were observed at multiple observatory locations for several hours on 17 January 2013. During the wave activity period, a duskside relativistic electron precipitation (REP) event was observed by one of the BARREL balloons, and was magnetically mapped close to GOES-13. We simulate the relativistic electron pitch-angle diffusion caused by gyroresonant interactions with EMIC waves using wave and particle data measured by multiple instruments on board GOES-13 and the Van Allen Probes. We show that the count rate, the energy distribution and the time variation of the simulated precipitation all agree very well with the balloon observations, suggesting that EMIC wave scattering was likely the cause for the precipitation event. The event reported here is the first balloon REP event with closely conjugate EMIC wave observations, and our study employs the most detailed quantitative analysis on the link of EMIC waves with observed REP to date.

Li, Zan; Millan, Robyn; Hudson, Mary; Woodger, Leslie; Smith, David; Chen, Yue; Friedel, Reiner; Rodriguez, Juan; Engebretson, Mark; Goldstein, Jerry; Fennell, Joseph; Spence, Harlan;

Published by: Geophysical Research Letters      Published on: 12/2014

YEAR: 2014     DOI: 10.1002/2014GL062273

BARREL; EMIC waves; GOES; pitch angle diffusion; RBSP; relativistic electron precipitation; Van Allen Probes