Gas dynamic control of arc voltage and power of plasma torch

Plasma torch with gas dynamic and magnetic arc stabilization in the discharge volume has been constructed and tested. Principally it is a linear type plasmotron with cylindrical stepwise channel consisting of the following main elements: 1) cathode - copper flat head with welded or pressed W or Hf electrode depending on the used gas; 2) anode - copper with a narrow region of plasma channel; 3) solenoid creating magnetic field parallel to the plasmotron axis and circulated so that for a nominal arc current the spot should perform optimum number of rotations. Different types of cathodes are discussed and a plexiglass model of a cathode with gas dynamic fixation is presented. A scheme of the plasmotron layout with gas dynamic control of the arc voltage is supported with a graphic representation of the arc voltage variation with the ratio of the gas consumption through the main gas distributer and through the tangential apertures in the cathode bottom. 5 figs., 1 tab., 4 refs