Experimental Study of the Effect of External Inductance on Pinch Characteristics and Neon Soft X-Ray Yield in Filippov-Type Plasma Focus Device

Abstract

So far, the detailed experimental effect of the inductance on the X-ray yield in the Filippov-type plasma focus devices has not been documented in literature. In this paper, a 90 kJ Filippov-type plasma focus device is used to investigate the effect of three different external inductances (20, 40, and 60 nH) on the pinch current and neon soft X-ray (SXR) yield experimentally. The obtained results for the three inductances show that the 60 nH inductance produces maximum pinch current for high voltages (12–13 kV). The results also show that with using 60 nH external inductance, a larger fraction of maximum current is transferred into the plasma column. Experimental results show that the ratio of pinch to maximum currents for 60 nH is larger than for the two other external inductances. The effect of external inductance on the neon soft X-ray emission at constant pressure (0.25 Torr) and different voltages (10–13 kV) is investigated with a five-channel diode X‑ray spectrometer. Of the three external inductances, the average neon SXR yield has a maximum value at 11 kV for 40 and 60 nH, and 12 kV for 20 nH. The maximum neon SXR yield energy is 24.87 ± 2.52 J for the external inductance 20 nH at 12 kV and it is 23.62 ± 3.10 J for the external inductance 40 nH at 11 kV and 5.23 ± 1.15 J for external inductance 60 nH at 11 kV. Experimental results show that with increasing of external inductance, the maximum neon SXR decreases.