Startup and Quasistationary Drive of Plasma Current by Lower Hybrid Waves in a Tokamak

Abstract

A plasma current is initiated and raised to a quasistationary level of about 20 kA by injection of the lower hybrid wave into a cold and low-density plasma produced by electron cyclotron resonance. The plasma current rises more slowly than the experimentally obtained $\frac{{L}_{p}}{{R}_{p}}$ magnetic diffusion time of the bulk plasma. The current rise time is inversely proportional to the bulk electron density, and agrees well with the collision time of the current-carrying high-energy electrons with the bulk plasma.