Capacitive probe measurements during RF heating on textor

Measurements with a capacitive probe, capable of withstanding the high heat loads during auxiliary heating, have been performed on an ICRF heated tokamak. The amplitude of the signal at the generator frequency measured by the capacitive probe corresponds to values of a few hundreds volts peak to peak at 1 MW of ICRF power, thereby confirming earlier measurements, at lower power on the URAGAN 3 [1,2,3] torsatron and on the RF test facility RFTF [4]. A theoretical model of the capacitive probe shows that these potential oscillations are probably related to ion Bernstein waves.