Characteristics of plasma flow from a pulse vacuum arc

Parameters of a plasma flow produced with a pulsed vacuum arc are studied by a set of diagnostic techniques. As materials of the cathode, the metals with distinguished electrophysical feathers (Al, Mg, Ti, Zr) are used. The arc current is of a quasi-rectangular shape of 200 mus length and about of 100 A amplitude. Distributions of ions of the cathode plasma flow over energy per a discharge unit E/Z was measured by a movable small-size electrostatic analyzer. It was shown that the most likely energies E_m/Z of distributions at 30 mus after the arc onset (Stage I) are markedly higher than these at the quasi-steady-state stage, i.e. at 100 mus after the onset (Stage II). Namely, E_m/Z at Stage I are close for different metals and equal about of 70 eV. These ones at Stage II are rather less and are of about 45 eV. The widths and peak values of the distributions at Stage I far exceed these at Stage II, as well. A significant dependence of the energy distributions shape on angle between axis of the entrance tube of the analyzer and axis of the plasma flow is also found.