A multiple-cathode arc-discharge plasma source

A plasma source for obtaining a 1-cm length of high-fractional ionized plasmas with electron densities in the range of 10¹⁵-10¹⁷ cm^-3 is described. The source consists of a capacitive discharge between a metal anode and an array of small metal cathodes embedded in epoxy, each with a current-limiting resistor. The effect is to have an array of sources which merge into each other, producing the plasma as a whole. The design and performance of the plasma source are presented. The entire system consists of the main electrode and shielding structures, the preionization circuit, and the main discharge circuit. Each of these components is described and the operating parameters and results are given