Arc cathode current density measurements

Detailed examination of the cathode arc tracks left by a discharge driven magnetically at high speed over prepared metal surfaces has yielded cathode root current density values of about 2 × 107A cm−2on copper and about 5 × 106A cm−2on brass. Individual electron emission sites on the cathode appear to have a lifespan not exceeding 10−7s, thereby accounting for the good correlation between current density values obtained for continuously burning arcs and those operating in multi-microsecond pulse modes.