MAVEN observation of magnetosonic waves in the Martian magnetotail region

Abstract

Magnetosonic waves are an important medium for energy transfer in collisionless space plasma. Magnetosonic waves have been widely investigated in the upstream of the bow shock at Mars. These waves are believed to originate from pickup ions or reflected particles. By utilizing MAVEN spacecraft data, we have observed the occurrence of quasi-perpendicularly propagating magnetosonic emissions near the proton gyrofrequency in the Martian magnetotail region. These plasma waves are associated with a significant enhancement of proton and oxygen flux. The excited magnetosonic waves could possibly heat the protons through resonance and facilitate the ionospheric plasma escape. Our results could be helpful to better understand the Mars’ magnetospheric dynamics and offer insights into possible energy redistribution between waves and plasma in the Martian nightside magnetosphere.