Source of metal ions with a variable velocity

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 plasma jet is variable at a wide range of values. When the discharge current is enhanced from 0.6 kA up to 11 kA, the velocity of plasma jet at a distance of 35 cm from the copper cathode is risen linear from 2-10⁶ cm/s up to 7-10⁶ cm/s, i.e. near six times exceeds the corresponding value for DC arc. A simple hydrodynamic model is presented, which explains the experimental results with a satisfactory accuracy.