Computation of pinch current in the Filippov type plasma focus

Summary form only given, as follows. Plasma focus devices generate a hot dense plasma, which produces a considerable amount of neutron. Experimental data on neutron yield have indicated a scaling law for neutron yield per pulse, as a function of pinch current. In this work the modified slug model which is proposed to describe the current sheath motion in Mather type PF devices, has been used in a fashion suitable for Filippov type PP, and by means of it we compute the trajectory of the plasma and electric discharge current as a function of time. In the first order approximation we assume that all of the discharge current pass through the plasma sheath. Then we computed the current at pinch moment in different voltages and pressures. The results show that in a definite voltage, there is an optimum pressure for which, the pinch current has maximum value. Besides, the results show that, by increasing the voltage, this optimum pressure shifts to higher values. The comparison of these computed results with the experimental data from Dena 90 KJ Filippov type plasma focus, show that the maximum values of pinch current are obtained at the same pressure for which the maximum mean neutron yield is observed.