Turbulent Heating of Plasma by Means of a Current

The authors present the results of turbulent plasma heating experiments in mirror and closed magnetic traps'under widely varying experimental conditions. The plasma heating effect is explained by the collective interactions that occur when the electron current velocity exceeds a certain critical value. A high noise level is then observed in the plasma, the resistance of the plasma becomes abnormally high, and the energy of the external current source is imparted to the plasma electrons and ions with an efficiency much greater than that achieved with energy dissipation methods governed by pair collisions. In the magnetic mirror trap experiments the plasma density varied between 1012and 4 x 1013 cm-3 and the quasi-stationary magnetic field from 1 to 25 kOe. The authors studied the efficiency of turbulent heating, the heating energy balance, and particle and energy losses both along and across the magnetic field. It was shown that increases in the longitudinal electric field producing the current in the plasma are accompanied by increases in the strength of the quasi-stationary magnetic field, ensuring minimum plasma.energy and particle losses during the passage of the heating current. The dependence of the efficiency of turbulent heating on the strength both of a quasi-stationary magnetic field and of a highfrequency longitudinal electric field was studied in toroidal magnetic traps. Using non-contact diagnostic methods (investigation of the epithermal radiation of the plasma in the region of the electron plasma frequency, non-coherent scattering in the plasma of u.h.V electromagnetic waves, etc. ), the authors analysed the oscillation spectrum of the turbulent plasma. Plasma containment after turbulent heating was studied in a toroidal trap with a strongly corrugated magnetic-field; the plasma density was 1012 - 1013 cm-3 and the pressure of the turbulently heated plasma nT ∼ 1015 - 1016 eV. cm-3. (author)