The effect of the helical winding HF current on the To-1 tokamak discharge

The effect of the high frequency current running along the helical winding inside the tokamak discharge chamber on the plasma is studied. The discharge current pulse was of rectangular shape with 100-150 ms duration and 15 kA amplitude. There were short (of 10-15 periods) damping current pulses excited in the helical winding at 20 kHZ and 1.5 kA initial amplitude. Basic attention was paid to magnetic probing of poloidal magnetic field HF disturbances. The effect of short HF pulses on the tokamak discharge has been shown to depend on the safely factor. At q approximately 6-8, the HF current results in exciting poloidal magnetic field disturbances with standing wave-like spatial distribution and frequency coinciding with that of the helical winding current. At q approximately 4, it causes strong helical instability and the discharge disruption