[IGPP Everyone] Final Seminar of the Quarter - Friday - EPSS Space Physics seminar announcement - Friday December 3 2021 - 03:30 PM Pacific Time (US and Canada)

[Sowmendran, Margie (IGPP)]

Final Seminar for the Fall Quarter
F R I D A Y - 12/3/2021

SPACE PHYSICS SEMINAR

DEPARTMENT OF EARTH, PLANETARY, AND SPACE SCIENCES
DEPARTMENT OF ATMOSPHERIC AND OCEANIC SCIENCES
UNIVERSITY OF CALIFORNIA, LOS ANGELES

ZOOM LINK PROVIDED BELOW

 https://ucla.zoom.us/j/92101918782?pwd=Z2o5RmI4OEpBWW4zcG1DZStIUWgrZz09




Understanding the Relativistic Electron Precipitation: Combined effect of Electromagnetic Ion Cyclotron and Whistler-mode Waves

Muhammad Fraz Bashir
EPSS, UCLA

Energetic electron losses in the Earth's inner magnetosphere are determined by outward radial diffusion and scattering into the atmosphere by various electromagnetic waves. The two most important wave modes responsible for electron scattering are electromagnetic ion cyclotron (EMIC) waves and whistler-mode waves (whistler waves) that, acting together, can provide rapid electron losses over a wide energy range from few keV to few MeV. Wave-particle resonant interaction resulting in electron scattering is well described by quasi-linear diffusion theory using the cold plasma dispersion, whereas the effects of nonlinear resonances and hot plasma dispersion are less well understood.
In this presentation, I consider the combined effect of EMIC and whistler-mode waves, including nonlinear resonances and hot plasma effects. The first part of the presentation is focused on an event during which both wave-modes are quasi-periodically modulated by ULF waves, observed by THEMIS.  Based on observed wave properties and plasma parameters, the test particle simulations and hot plasma EMIC waves dispersion analysis reveal that nonlinear phase trapping of 300-500 keV electrons through resonances with whistler waves may accelerate and make them resonant with EMIC waves that, in turn, quickly scatter those electrons into the loss-cone. The second part of the presentation is focused on the hot plasma model for EMIC waves applicable to a wide range of plasma and hot ion characteristics. I show preliminary results of a parametric study based on few events observed by THEMIS and discuss how this model may provide a generalized hot plasma effect for realistic quasi-linear diffusion rate calculations. The third part of the presentation considers events with conjugated equatorial measurements of ULF-modulated EMIC and whistler-mode waves and low-altitude measurements of electron precipitations by UCLA ELFIN CubeSats.



Friday, December 3,  2021
3:30 - 5:00 PM

In-Charge:  Marco Velli

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.igpp.ucla.edu/pipermail/everyone/attachments/20211201/a5e71b2f/attachment.html>