The acceleration of electrons and ions associated with low-hybrid heating is studied. This acceleration takes place under the effect of parametrically excited plasma turbulence. For pump frequencies well above the low-hybrid frequencies the nonlinear effects lead to plasma heating and fast electron generation. For pump frequencies close to the low-hybrid frequencies modulational instability and collapse take place. These processes result in small groups of ions accelerating. It is shown that development of parametric instability sharply increases current drive efficiency. An explanation of the current drive density limit is presented.
Lower hybrid heating in the Alcator A tokamak