Thermal electron acceleration by localized bursts of electric field in the radiation belts

Abstract

AbstractIn this paper we investigate the resonant interaction of thermal ∼10–100 eV electrons with a burst of electrostatic field that results in electron acceleration to kilovolt energies. This single burst contains a large parallel electric field of one sign and a much smaller, longer‐lasting parallel field of the opposite sign. The Van Allen Probe spacecraft often observes clusters of spatially localized bursts in the Earth's outer radiation belts. These structures propagate mostly away from the geomagnetic equator and share properties of soliton‐like nonlinear electron acoustic waves: a velocity of propagation is about the thermal velocity of cold electrons (∼3000–10,000 km/s), and a spatial scale of electric field localization along the field lines is about the Debye radius of hot electrons (∼5–30 km). We model the nonlinear resonant interaction of these electric field structures and cold background electrons.