Arc cathode current density measurements

Abstract

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 × 10⁷ A cm⁻² on copper and about 5 × 10⁶ A cm⁻² on brass. Individual electron emission sites on the cathode appear to have a lifespan not exceeding 10⁻⁷ s, thereby accounting for the good correlation between current density values obtained for continuously burning arcs and those operating in multi-microsecond pulse modes.