High-Frequency Stabilization of Rotating Plasma Cylinder Perturbations Along a Magnetic Field

We have studied the effect of a longitudinal high-frequency current on the dynamics of long-wave in a plasma cylinder in an axial magnetic field. To excite the instability we rotated the plasma in quasi-stationary shear fields. The spatial and time characteristics of the instability were measured with a system of Langmuir probes. We found that with amplitudes of the HF current magnetic field Bφ, greater than a certain critical value Bk, the discharge instability vanishes. This effect of instability suppression has a threshold, and the magnitude of Bk satisfies the condition Bk/Bk ∼ const < KZ/Kφ. We discuss different mechanisms which may explain this phenomenon; in particular, a possible mechanism in these experiments may be a shorting of the polarization fields in the perturbation which occurs with periodic rotation of the total magnetic field vector relative to the wave vector KZ. (author)