Electron heating by lower hybrid waves in the PLT tokamak

Abstract
Lower hybrid waves with a narrow, high-velocity wave spectrum have been used to achieve high central electron temperatures in a tokamak plasma. Waves with a frequency of 2.45 GHz launched by a sixteen-waveguide grill at a power level less than 600 kW were used to increase the central electron temperature of the PLT plasma from 2.2 to 5 keV. Associated with this temperature increase was an apparent reduction in the central electron thermal diffusivity. The magnitude of the temperature increase depends strongly on the phase difference between waveguides and on the direction of the launched wave.