Pinch Current Limitation in Sahand Plasma Focus

Abstract

In this paper a new version of ML model has been used to simulate discharge dynamics in a 90 kj Fillipove type plasma focus, Sahand. Comparing model predictions with experimentally measured data shows that, the ML model when properly is fitted, is able to realistically simulate the discharge dynamics and consequently can be used to investigate the effect of operational and structural parameters on Sahand PF operation. To determine the optimum parameters which maximize the pinch current Ipinch, the effect of gas pressure and static external inductance L0, on discharge dynamics in Sahand were investigated. The obtained results show that, for fixed initial stored capacitor energy, there is an optimum gas pressure at which Ipinch has its maximum value. To further increase in Ipinch at the optimum pressure, the static inductance was reduced. The results indicated that there exists an optimum value of L0, where Ipinch reaches a maximum value and reducing L0 further will not increase Ipinch. The maximum Ipinch has been achieved at optimum low static inductance at the expense of reducing C.S velocity at the time of pinch. The results of this investigation can confirm the current pinch limitation indicated before for Mather type PFs, for a Fillipov type PF.