Internal free boundary problem for cold plasma equations

TL;DR

This paper investigates a free boundary problem in cold plasma physics, analyzing the interface dynamics between two media with different ion fields using Riemann problems and stability conditions.

Contribution

It introduces a novel approach to determine the free interface position in cold plasma equations via generalized Rankine-Hugoniot and stability conditions.

Findings

Derived conditions for interface stability.

Characterized the interface motion in cold plasma systems.

Provided a framework for analyzing free boundary problems in plasma physics.

Abstract

For the system of cold plasma equations describing the motion of electrons in the field of stationary ions, we consider the Riemann problem posed at an impenetrable interface between two media. These media differ in the magnitude of the constant ion field. The interface between the media is assumed to be free. Its position is determined from the generalized Rankine-Hugoniot conditions and the stability condition, that is, the intersection of Lagrangian particle trajectories at the interface.