Finite-Difference Multiple Fluid Solution for Source-Driven Rotation in Highly Magnetized Linear Plasma Device

TL;DR

This paper develops an analytical and numerical framework to study the rotation of multi-fluid magnetized plasmas, validating a finite-difference code against theoretical solutions and exploring viscosity effects.

Contribution

It introduces a validated finite-difference simulation method for multi-fluid plasma rotation, incorporating magnetic field evolution and viscosity effects, extending previous analytical results.

Findings

MITNS accurately reproduces analytical asymptotic solutions.

Viscosity dominates ion transport in certain parameter regimes.

Magnetic field evolution significantly affects plasma rotation dynamics.

Abstract

The rotation profile of a magnetized plasma cylinder composed of multiple fluids is investigated analytically, expanding on previous results. The analytic steady-state solution is used as a benchmark for a time-dependent multiple-fluid finite-difference code, MITNS: Multiple-Ion Transport Numerical Solver. Magnetic field evolution is taken into account, both analytically and numerically. Its details are shown to be of importance when particles are allowed out of the domain. MITNS reproduces the asymptotic expansion results for a small parameter $\delta\lll1$. For $\sqrt{m_e/m_i} \sim \delta \ll 1$, a slightly different regime, dominated by viscosity-induced transport of ions, is found numerically and analytically. This validation supports the use of this code for more complex time-dependent calculations in the future.