INVESTIGATION OF PLASMA PARAMETERS IN A STRONG MAGNETIC FIELD WITH THE AID OF DOUBLE ELECTRIC PROBES,

In view of the doubtful reliability of data obtained with probes on a plasma in a strong magnetic field, when the particle Larmor radius is comparable with the probe characteristic dimension, the authors have checked on the probe readings by other diagnostic means. The plasma parameters measured were electron temperature and charged-particle density at saturation. The electron temperature was determined by plotting the derivative of the current with respect to the voltage against the probe voltage. The charged-particle density was measured by determining the saturation current and also by measuring the derivative of the probe current with respect to the voltage in the vicinity of zero voltage. The effect of the probe size was also investigated. It is shown that the probe measurements deviate from the others by as much as 40 and become particularly unreliable in strong magnetic fields. Author