Simulations of Collisionless Perpendicular Shocks in Partially Ionized Plasmas

TL;DR

This study uses 2D hybrid particle simulations to explore how neutral particles influence the structure and particle acceleration in perpendicular collisionless shocks within partially ionized plasmas.

Contribution

It demonstrates the role of neutral particle leakage and pickup ion formation in modifying shock structures and inducing plasma instabilities.

Findings

Neutral particles leak into the upstream region.

Pickup ions are preferentially accelerated.

Plasma instabilities are excited by pickup ions.

Abstract

Perpendicular collisionless shocks propagating into partially ionized plasmas are investigated by two-dimensional hybrid particle simulations. It is shown that some neutral particles leak into the upstream region from the downstream region, the leaking neutral particles become pickup ions in the upstream region and modify the shock structure, the pickup ions are preferentially accelerated, and plasma instabilities are excited by the pickup ions in the upstream and downstream regions.