The vacuum spark as a source of metal ions with variable velocity

Abstract

Results of the time-of-flight measurements of the cathode plasma jet velocity in a low voltage vacuum spark are presented. It is found that the mean velocity of ions in the plasma jet varies over a wide range of values. When the discharge current increases from 0.6 to 11 kA the ion velocity at a distance of 35 cm from the copper cathode goes up to 7×104 m s−1, i.e. exceeds nearly six times the corresponding value of 1.3×104 m s−1 for the dc arc. The intensity of the ion beam in this case increases by more than two orders of magnitude.