Application of a Scale Normalization Technique for High Resolution Analysis of the Magnetosheath at Mars

Abstract

In order to study spatial distributions of global magnetosheath structures, physicists often rely upon spatial binning, whereby space is divided into cells, each filled with the average value of all spacecraft measurements within that cell. The traditional binning schema utilizes a fixed Cartesian grid of cube bins. The morphology of the magnetosheath's boundaries are not fixed, however, but driven by upstream and planetary conditions. Therefore, the spatial structures are not fixed in Cartesian space, and thus a Cartesian binning technique will produce a highly coarse grained spatial distribution. We propose an alternative binning technique utilizing a scale normalized dimensionless coordinate system defined in terms of magnetosheath morphology. To demonstrate the efficacy of this technique, we apply a basic implementation to the Martian system. We are thereby able to achieve a high-resolution spatial mapping of bow shock and magnetosheath processes and resolve spatial structures that are washed out when binned traditionally. In particular, we can resolve the shock overshoot, analyze the dominant forces acting at the shock, and obtain fine-scale distributions of the bulk ion plasma magnetosheath forces and thermalization mechanisms. Magnetic tension and magnetic pressure gradient are compared. The ion pressure divergence at the shock is found to significantly vary in line with the solar wind temperature anisotropy. The dependency of the mirror mode instability on location and Mach number, and its implications for thermalization processes in the small Martian magnetosheath are investigated.