Experimental Study of a Hollow-Cathode Argon Arc Plasma

摘要

A set of coaxial cathode tubes produced a plasma having the same characteristics as the plasma from a tubular hollow cathode. Measurements of the plasma characteristics by microwave interferometry, plasma sweeper, Langmuir probe, and measurements made with a new plasma tool--a plasma scanner--showed that the plasma is nearly completely ionized at 10 to the 13th power/cc ion density. The electron beam, originating in the cathode, was detected by means of the scanner. The electrons in the beam attain energies as high as two-thirds of the arc voltage drop. The ion temperature of 6.9 electron volts, which was deduced from plasma sweeper measurements and diffusion theory, could result from directed ion drift; the electron temperature of the plasma is 3 electron volts. (Author)