Theory of parametric heating of plasma in the lower hybrid frequency range
Abstract
Lower hybrid turbulence can be driven parametrically by a whistler pump wave. Destabilization occurring through the resonant interaction of the whistler, an electrostatic mode, and a particle, either electron or ion, which mechanism is akin to the wellknown phenomenon of inverse nonlinear Landau damping, is considered. A nonlinear theory of turbulence is developed for a range of parameters characteristic of tokamaks on the basis of the wave kinetic equation for weakly turbulent plasma in a uniform magnetic field. This yields an estimate of the saturation level of the turbulence which is, in turn, responsible for the anomalous absorption of the pump wave electromagnetic energy. Both the anomalous absorption rate and the plasma heating rate are evaluated. The theoretical results are very promising: lower hybrid parametric heating should be realizable up to densities typically of order 3×10^{14} cm^{3} (for larger densities, the poor tunneling of the pump wave through the evanescent region between the launching structure and the turning point leads to too high electric fields in the waveguide). A decisive advantage of this form of ratio frequency heating is that energy can also be deposited directly in the ion component.
 Publication:

Physics of Fluids
 Pub Date:
 January 1976
 DOI:
 10.1063/1.861308
 Bibcode:
 1976PhFl...19..108R
 Keywords:

 Particle Interactions;
 Plasma Heating;
 Wave Interaction;
 Whistlers;
 Destabilization;
 Kinetic Equations;
 Nonlinear Equations;
 Tokamak Devices;
 Vlasov Equations;
 Wave Equations;
 Plasma Physics