Kinetic description of wave induced plasma flow in the radio frequency domain

TL;DR

This paper develops a kinetic model for wave-induced plasma flows in strong magnetic fields, revealing how electric and magnetic field inhomogeneities influence plasma drifts relevant to tokamak applications.

Contribution

It introduces a kinetic framework accounting for both electric and magnetic field inhomogeneities in plasma flows, especially near cyclotron resonances, extending previous models that considered only one field component.

Findings

Electric and magnetic inhomogeneities cause plasma drifts.

Flows influence transport processes in tokamaks.

Kinetic corrections clarify behavior at cyclotron resonances.

Abstract

A model for ICRH induced flows in the presence of a strong magnetic field is presented. These flows are the finite temperature counterpart of flows existing in cold plasmas described e.g. in [D. Van Eester et al., Plasma Phys. Control. Fusion 55 (2013) 025002] and thus do not rely on the waves being damped. The kinetic corrections offer insight in what happens at cyclotron resonances. Authors commonly either rely on the confining magnetic field $\vec{B}_o$-field to be strong, or the electric field $\vec{E}$-field to be rapidly varying but are not accounting for both when writing down the solution of the equation of motion on the slow time scale. In this paper, the equation of motion is solved for constant $B_o$ to keep the discussion as simple as possible. The simultaneous presence of $\vec{B}_o$ and the $\vec{E}$-field inhomogeneity causes drifts perpendicular to the $\vec{B}_o$ and to other slow time scale accelerations, the Ponderomotive acceleration being one of them. Because of the first and having tokamak applications in mind, these flows - although small in magnitude - cause drifts that enter in competition with transport induced flows.