Stabilization of the current-driven electrostatic ion-cyclotron instability by lower-hybrid waves

The current-driven electrostatic ion-cyclotron instability in a Q machine operated in the low-density regime (ωpeωce)21 is stabilized by externally generated rf electrostatic fields in the lower-hybrid range. Stabilization is due to a resonant ponderomotive force, which reduces the instability frequency, thus increasing the ion-cyclotron damping. The experimental results are in good agreement with an analysis which describes the effect of rf power on the instability frequency shift and growth rate.