Optimization of neon soft X-ray yield in a low-energy dense plasma focus device

Abstract

The modified version of Lee model code is used in numerical experiments for characterizing and optimizing neon soft X-ray yield ([Formula: see text]) of the United Nations University/International Center for Theoretical Physics Plasma Focus Facility (UNU/ICTP PFF) device operated at 14 kV and 30 [Formula: see text]. In our present work, the neon yield [Formula: see text] is improved with an optimized UNU/ICTP PFF device by computing the optimum combination of static inductance ([Formula: see text]), anode length ([Formula: see text]), anode radius ([Formula: see text]) and cathode radius ([Formula: see text]), keeping fixed their ratio ([Formula: see text]) at 3.368, through a lot of numerical experiments at six operating pressures ([Formula: see text]). At lower [Formula: see text] (e.g. 2.0, 2.5 and 3.3 Torr), the optimum [Formula: see text] value, together with the corresponding optimum combination of [Formula: see text], [Formula: see text] and [Formula: see text], is found to be 15 nH, whereas at higher [Formula: see text] (e.g. 4.0, 5.0 and 6.0 Torr), it is obtained as 10 nH. Though the computed maximum neon yield [Formula: see text] (57.2 J with the corresponding efficiency of 1.94%) is found at [Formula: see text], assuming an achievable range of incorporating low-inductance technology, the best optimum combination of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] is found to be at [Formula: see text], resulting in the computed optimum neon yield [Formula: see text] of 54.60 J with a corresponding efficiency of 1.9%. This computed neon yield [Formula: see text] is about 11 times higher than the measured value [Formula: see text] at optimum [Formula: see text] of UNU/ICTP PFF. It is also observed that our computed neon yield [Formula: see text] is improved by around six times from the previously computed value, which was 9.5 J at the optimum [Formula: see text] Torr for optimum anode configuration of this machine. In addition, neon yield [Formula: see text] is obtained with our optimized combination of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] at 11.5 kV and compared with the measured neon yield [Formula: see text] of the NX2 machine.