Effect of Impurities on the Exclusive Parameters of Plasma-Focus Dena

Fusion performance of a plasma-focus is negatively affected by the presence of impurities that originated from the countereffect of the current sheath and the electrodes, which lower the plasma temperature and dilute the reacting deuterons. The experimental results of the Filippov-type plasma-focus Dena (90 kJ, 25 kV, and 288 $\mu\hbox{F}$) demonstrate the profound influence of anode insert materials on the exclusive parameters of the device. The spike depth, the average of the second derivative of current $V_{\rm imp}$, and the hot spots are the parameters that clearly display the effect of impurities on the pinch structure and consequently the radiations emitted from the compressed region.