DIAGNOSIS AND STUDY OF THE CATHODIC REGIO N OF AN ELECTRIC-ARC

Spectroscopic diagnostic of the cathode region of an electric are has showed, that in this zone the norm intensity of ArI spectral lines, co rresponding to the norm temperature, varies considerably with the dist ance from the cathode. In order to explain this effect, many possible physical phenomena are considered. A comparison of influences of these phenomena plasma shows that specific comportment of the plasma in the vicinity of the cathode tip may be correctly explained by existence o f a hydrodynamic effect and particulary by a gradient of pressure insi de the plasma.