Test-Particle Simulation of the Interaction of Hot Electron Velocity Distribution with the Fine Structure of Chorus Emissions

Abstract:

We conduct a test-particle study of the interaction between hot electrons and a parallel-propagating rising-tone lower band chorus emission. The wave field is based on a model that utilizes the nonlinear theory of chorus growth and incorporates a realistic subpacket structure. Electrons are traced back in time and with the use of Liouville's theorem and assumptions on the initial, unperturbed distribution, the effect of the wave-particle interaction on hot electron velocity distribution is reconstructed. The perturbed distribution reveals a series of stripes of increased and decreased phase space density. Each stripe is associated with an electromagnetic hole structure which exists along the resonance velocity curve of each subpacket. Time-averaging of the perturbed distribution shows that rising-tone lower band chorus emissions produce a sharp decrease in electron density at low parallel velocities, which might be detectable by spacecraft particle instruments.