Experiments on potential gradients in a current-carrying plasma. I. Potential structures

In a current-carrying plasma with vd<vte, constant potential gradients and strong localized potential jumps have been observed under different experimental conditions. One or more potential jumps with eΦ/kTe =10–12 and a typical width of 30–500 λDe may exist. Measurements of the electron distribution function show the presence of a beam on the high-potential side. This electron beam is thermalized within 500–1000 λDe leading to strong localized electron heating. Ion heating as well as peaked anomalous resistivity are found within the jump. In the case of a constant potential gradient, ion and electron heating have been observed. However, no electron beam could be detected. The resistivity is anomalous for this case also.