Two-components ion flow in a low voltage vacuum spark

Abstract

Ion velocities in cathode plasma flow of a low voltage vacuum spark have been studied experimentally for peak discharge currents of 1 -10 kA. Experiments have been performed using the time-of-flight technique at different ranges of ion collector from the discharge gap. It is shown that there are t w o ion components in the cathode flow. The slow one presents the bulk of ion distribution and at low peak discharge current its velocity is closed to the convenient value for vacuum arc. The fast components' velocity is a few times higher than one for slow ions and amplitude of current for these ions at a range of 10 cm from the discharge gap was closed to one for the slow component. As the distance increases, peak of the fast ions decreases sharper than one for the slow component. Amplitudes of signals and mean velocities of both ion components increase sharply with the discharge current. The fast ion component corresponds, apparently, to beam of the multiply charged ions that had been found by the authors earlier. Total amount of these ions attains, approximately, IO" ions per a pulse.