Turbulence in Confined Plasmas at High Electric Fields

Magnetically confined plasmas carrying a relatively large current in the direction of the main magnetic field are considered in regimes where the applied electric field is larger than the runaway critical field. The plasma is assumed to be turbulent with a relatively low fluctuation level induced by ion sound waves, Langmuir waves, and ion cyclotron waves. Three aspects of the problem are examined: (a) The transfer of momentum within the electron distribution from superthermal velocities to thermal velocities, i.e. the inhibition by turbulence of the runaway process; (b) the anomalous (larger than collisional) heating of the ion energy distribution tail; (c) the transfer of momentum from slow electrons to ions by ion-sound waves and classical collisions. (author)