Minimum ohmic dissipation and DC helicity injection in tokamak-like plasmas

Abstract

The current and magnetic field profiles of a steady-state, tokamak-like plasma sustained by DC helicity injection are determined by assuming that the plasma relaxes to a state where the ohmic dissipation rate is minimum. Helicity balance is imposed as a constraint and the basic features required for DC helicity injection, a pair of electrodes magnetized by an externally produced flux, are included in a 2D model. The field is calculated self-consistently and only the values of experimentally controllable parameters are used.