Magnetosphere Seminars

Apr 1, 2014 – “Nonlinear Electric fields and Dipolarization Fronts in the Inner Magnetosphere”

Speaker:David Malaspina (LASP)
Date:Tuesday, Apr 01, 2014
Time:4:00 PM
Location:LASP Space Science Building, room N248 upstairs. Map

Seminar Abstract:

Van Allen Probes observations are presented which demonstrate that dipolarization fronts penetrating Earthward of geosynchronous orbit lead to 1) localized enhancements of 1-30 keV electron fluxes and 2) formation of nonlinear electric field structures at the radial distances where wave-particle interactions drive outer radiation belt energization. Nonlinear electric field structures include nonlinear chorus, double layers, and phase space holes, many of which contain large amplitude electric fields, including parallel electric fields, that can act to accelerate electrons. Using nonlinear electric fields as a marker to identify dipolarization fronts, it is found that geosynchronous-penetrating dipolarization fronts are much more frequent than previously reported and that in some cases only interaction with the plasmapause boundary halts their Earthward motion.