Current drive via magnetohydrodynamic helicity waves

Abstract

We explore fundamentals of low-frequency current drive produced by a packet of arbitrarily polarized nonlinear shear Alfv\'en waves in an infinite, uniform magnetized plasma. Analysis of the magnetohydrodynamic equations with resistivity and viscosity yields coupled nonlinear equations for the Alfv\'en wave amplitude and an induced magnetic field. Particular solutions relate the plasma current to the helicity of the Alfv\'en wave and the difference between the viscosity and magnetic diffusivity.