Evidence of Anomalous Diffusion in a Radio-Frequency Discharge in a Magnetic Field

Abstract

Experimental evidence of anomalous diffusion in argon and helium 29.3 Mc/sec rf discharges immersed in a static longitudinal magnetic field is described. It was observed that as the magnetic field is increased from zero, the rf voltage and power required to sustain a constant density discharge initially decrease but start to rise when a critical magnetic field Bc is reached. The rise is accompanied by a sudden onset of low-frequency fluctuations. The results are compared with those obtained by others for dc and ac discharges. In contrast to the ac experiments, where application of kilocycle and tens of kilocycle currents results in higher Bc than in the dc experiments, application of 29.3 Mc/sec currents results in the onset of an instability at lower magnetic fields.