THE PROPAGATION OF ION-CYCLOTRON WAVES IN A Q-MACHINE

Phase measurements of the ion cyclotron instability driven by an electron drift parallel to a magnetic field are presented. The experiment was performed in a Q-machine (n approximately 1010 cm-3, T i=Te=0.2 eV, B approximately 0.2 T) and the measurements made using digital signal processing techniques. The propagation characteristics of the ion cyclotron waves were determined by making measurements in the radial, axial and azimuthal directions. The effect of plasma density, magnetic field and electron drift velocity on the phase of the waves was investigated. The authors analyze the data in the light of the Drummond-Rosenbluth theory and make comparisons with the 2-D potential driven model.