Ion Temperature Effects on Plasma Flow in the Magnetic Mirror Configuration

TL;DR

This study investigates how finite ion temperature influences plasma flow acceleration in magnetic mirror configurations using a two-fluid MHD model, highlighting the effects of ion pressure, anisotropy, and ionization processes.

Contribution

It introduces a comprehensive analysis of ion temperature effects on plasma acceleration, including the role of sonic point regularity and ion pressure anisotropy, with validation through time-dependent simulations.

Findings

Sonic point regularity determines global plasma acceleration solutions.

Ion pressure anisotropy, especially the mirror force, enhances plasma acceleration.

Time-dependent solutions converge to stationary solutions, confirming stability.

Abstract

Effects of finite ion temperature on plasma flow in the converging-diverging magnetic field, the magnetic mirror, or equivalently, magnetic nozzle configuration, are studied using a quasineutral paraxial two-fluid MHD model with isothermal electrons and warm magnetized ions. The ion acceleration was studied with an emphasis on the role of the singularity at the sonic point transition. It is shown that the regularity of the sonic point defines a global solution describing plasma acceleration from subsonic to supersonic velocity. Stationary accelerating solutions were obtained and compared with the time dependent dynamics, confirming that the solutions of the time-dependent equations converge to the stationary solutions and therefore are stable. The effects of the ion pressure anisotropy were analyzed using Chew-Goldberger-Low model and its generalization. It is shown that the mirror force (manifested by the perpendicular ion pressure) enhances plasma acceleration. The role of ionization and charge exchange on plasma flow acceleration have been investigated.