Nonlinear Ohmic Dissipation in Axisymmetric DC and RF Driven Rotating Plasmas

TL;DR

This paper investigates nonlinear Ohmic dissipation in axisymmetric plasmas driven by DC and RF fields, revealing how inertial effects lead to charge relaxation and affect angular momentum dynamics.

Contribution

It introduces a nonlinear conductivity mechanism arising from inertial effects and analyzes its impact on plasma charge separation and angular momentum.

Findings

Nonlinear Ohmic response due to inertial effects causes charge relaxation.

The quality factor of angular momentum storage is independent of charge separation details.

Wave-driven angular momentum generation efficiency is characterized.

Abstract

An axisymmetric fully ionized plasma rotates around its axis when a charge separation between magnetic surfaces is produced from DC fields or RF waves. On each magnetic surface both electrons and ions obey the isorotation law and perform an azimuthal E cross B rotation at the same angular velocity. When Coulomb collisions are taken into account such a flow displays no Ohmic current short circuiting of the charge separation and thus no linear dissipation. A nonlinear Ohmic response appears when inertial effects are considered, providing a dissipative relaxation of the charge separation between the magnetic surfaces. This nonlinear conductivity results from an interplay between Coriolis, centrifugal and electron-ion collisional friction forces. This phenomena is identified, described and analyzed. In addition, both the quality factor of angular momentum storage as well as the efficiency of wave driven angular momentum generation are calculated and shown to be independent of the details of the charge separation processes.