Direct evidence for efficient scattering of suprathermal electrons by whistler mode waves in the Martian magnetosphere

Abstract

Whistler mode waves are critical emissions in magnetized plasmas that usually influence the electron dynamics in a planetary magnetosphere. In this paper, we present a unique event in the Martian magnetosphere in which enhanced whistler mode waves (~10−11 V2/m2/Hz) with frequency of 0.1 fce–0.5 fce occurred, based on MAVEN data, exactly corresponding to a significant decrease of suprathermal electron fluxes. The diffusion coefficients are calculated by using the observed electric field wave spectra. The pitch angle diffusion coefficient can approach 10−2 s−1, which is much larger, by ~100 times, than the momentum diffusion coefficient, indicating that pitch angle scattering dominates the whistler–electron resonance process. The current results can successfully explain the dropout of the suprathermal electrons in this event. This study provides direct evidence for whistler-driven electron losses in the Martian magnetosphere.

Keywords

• whistler mode waves
• diffusion coefficients
• electron scattering
• martian magnetosphere