Small scale magnetosphere: Laboratory experiment, physical model and Hall MHD simulation

TL;DR

This study combines laboratory experiments, analytical models, and Hall MHD simulations to investigate mini-magnetospheres around weakly magnetized bodies, revealing the role of Hall effects and ion inertia in their structure.

Contribution

It provides the first experimental evidence of Hall term effects in mini-magnetospheres and develops an analytical model explaining key features observed in simulations.

Findings

Hall magnetic field generated by Hall term observed experimentally.

Differences in magnetopause position linked to ion inertia length.

Simulation results agree with experiments and analytical model.

Abstract

A problem of magnetosphere formation on ion inertia scale around weakly magnetized bodies is investigated by means of laboratory experiment, analytical analysis and 2.5D Hall MHD simulation. Experimental evidence of specific magnetic field generated by the Hall term is presented. Direct comparison of regimes with small and large ion inertia length revealed striking differences in measured magnetopause position and plasma stand off distance. Analytical model is presented, which explains such basic features of mini-magnetosphere observed in previous kinetic simulations as disappearance of bow shock and plasma stopping at Stoermer particle limit instead of pressure balance distance. Numerical simulation is found to be in a good agreement with experiments and analytical model. It gives detailed spatial structure of Hall field and reveals that while ions penetrate deep inside mini-magnetosphere electrons overflow around it along magnetopause boundary.