Angular Distributions of Plasma Flows in a Vacuum Arc with Boride Cathodes

Abstract

Results of investigation of the angular distribution and mass-to-charge fractions of the ion flow generated in a pulsed vacuum arc with lanthanum hexaboride and boron carbide cathodes are presented. It is shown that the discharge with such cathodes provides efficient generation of the plasma with a high fraction of boron ions with charge states from 1+ to 3+ whose total fraction is determined by the fraction of the boron atoms in the cathode material. The angular distributions of ions in the plasma flow depend on the relationship between the masses of components of cathode materials: in the case of lanthanum hexaboride cathode, the distribution of boron ions is wider than that of lanthanum ions, and in the case of boron carbide cathode, the boron and carbon ion distributions are practically identical.