OBSERVATIONS OF PLASMA DYNAMICS IN THE VACUUM SPARK

Experimental observations are presented of a vacuum spark driven by a low impedance pulse forming line delivering 100 kA to the load. A pulsed laser is used to form a preionizing plasma on the cathode. The combination of axial and radial optical streak camera observations, together with the time and space resolved soft x-ray emission, permit the evolution of the plasma dynamics, density and temperature to be measured. Three kinds of behavior are observed according to axial position. A close correlation is found between the x-ray and the optical emission, with the observation of micropinch formation. A discussion is presented in which the behavior of the vacuum spark under differing operating conditions is compared. (C) 1995 American Institute of Physics.