Low frequency proton resonance waves and associated higher frequency waves in the Martian magnetosheath and their role on ion escape

Abstract:

Strongly compressional waves, with the magnetic field wave perturbation amplitude being nearly twice that of the average total background field strength, are commonly observed at Mars in the magnetosheath by the MAVEN spacecraft. These waves are left-handed polarized and have a frequency in the spacecraft frame close to that of the local average proton gyrofrequency. These waves are similar to the large amplitude, low frequency waves observed in the foreshock and upstream regions of the Martian space environment. This presentation is focused on high frequency waves often observed in association with the low frequency waves, for instance the presence of electron phase holes together with other solitary structures. One of the events is observed on the flank of the magnetosheath where only the tailward propagating protons are present. Analysis using LPW electric field measurements to investigate how waves in the sheath interact with the local plasma and ionosphere, driving planetary ion escape is the main goal of this work.