The influence of the insulator surface in the plasma focus behavior

The insulator (Pyrex glass pipe in our system) surface alteration suffered due to successive plasma focus discharges was found to be responsible for the improvement in stabilization in the plasma focus behavior. The development of microscopic conductive sites (∼1 μm in size), observed on the insulator surface due to the accumulation of successive discharges, increases the efficiency, by a metal-insulator-metal process, on current sheath buildup with an increment in current density during the breakdown. The influence of the surface in the early stage of the discharge, and its correlation with the intensity of the pinch, was studied by analyzing the Si concentration on the surface of the targets of AISI 304 exposed to the plasmas and ion beams generated in the discharge for different experimental situations.