Spatial structure, dynamics and electron heating of cathode jet of a pulse vacuum discharge

Abstract

Results of experimental studies of energy and charge state distributions of ions in a cathode plasma jet of a high-current vacuum discharge are presented. Measurements have been carried out by a time-of flight method with an electrostatic energy analyzer. Ions of cathode material with the charge states up to Z=+11 have been observed. Significant increase of the mean ion charge and the ion energy in compare both with the low-current discharges and with the steady-state arcs has been obtained. With the peak discharge current about 2.5 kA and the rate of current rise I/spl dot/=3/spl middot/10/sup 9/ A/s the mean ion charge state equals Z=6.4 and the mean ion energy for different ion species was within range 1.3-1.8 keV. These results are explained by pinching of the cathode jet by magnetic field of its current which occur at high values of I and the region of ions generation is rather less than the size of cathode jet.