Nonlinear Evolution of the Mirror Instability in the Magnetosheath Using PIC Simulations

Abstract:

Mirror modes are large amplitudes nonpropagating structures frequently observed in the magnetosheath as trains of magnetic peaks or magnetic holes. Observational studies have shown that the shape of mirror structures is related to local plasma parameters and distance to the mirror instability threshold. We study the nonlinear evolution of mirror modes using Particle in Cell (PIC) simulations. We change the plasma conditions by artificially enlarging the simulation box over time to resemble the plasma expansion in the vicinity of the magnetopause which leads to changing the plasma conditions toward a more mirror stable state and investigate the final nonlinear state of the mirror structures.