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 I_pinch, 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 I_pinch has its maximum value. To further increase in I_pinch at the optimum pressure, the static inductance was reduced. The results indicated that there exists an optimum value of L₀, where I_pinch reaches a maximum value and reducing L₀ further will not increase I_pinch. The maximum I_pinch 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.