Gas-puff z-pinch plasmas driven by inductive voltage adder-inductive energy storage pulsed power generator ASO-X

Abstract

Gas-puff z-pinch plasmas are driven by an inductive voltage adder -inductive energy storage pulsed power generator "ASO-X and the behavior of plasma column and the spatial distribution of hot spots are investigated. ASO-X has the performance of the maximum output voltage and current are 180 kV and 400 kA respectively and can provide a fast current rise rate with the plasma opening switch (POS). By using ASO-X with operating POS the stability of plasma column and the spatial distribution of hot spots are improved. I. INTORODUCTIONGas-puff z-pinch plasmas [l], [2] have possibilities as a soft X-ray source for the lithography method [3], X-ray microscopy and a breakthrough in X-ray laser [4] because they can produce comparatively high temperature and density plasmas with compact and simple equipment. But it is difficult to produce stable and reproducible plasmas or hot spots [5] due to lack of the uniformity of injected gas distributions [6], [7] and insufficient the current value and rise time flowing through the plasmas in the experimental conditions. These conditions cause Rayleigh-Taylor instabilities and so on in the z-pinch plasmas. In order to improve the uniformity of the injected gas between the electrodes, using a mesh cathode is one of the solutions. By the influence of a reflection of the injected gas on the cathode surface, the flow of the gas is fallen into disorder then the uniformity of the gas distribution between the electrodes becomes deficient.The influence of the gas reflection on the mesh cathode is less compared with that using a solid cathode. In our previous work an inductive energy storage pulsed power generator ASO-I1 was used as a power source then the stability of plasma column and the reproducibility of hot spots could be improved by using the mesh cathode and wire fuses as an opening switch [SI. But it is not enough to apply the z-pinch plasmas for the practical applications. Therefore a new pulsed power generator ASO-X [9] is used as a power source for the z-pinch plasmas. ASO-X is using an inductive voltage adder technology and can provide a very fast rise time current to the load by operating Plasma Opening Switch (POS). In this paper the experimental results of the gas-puff z-pinch plasmas driven by ASO-X for the purpose of improving the stability of plasma column and the spatial distribution of hot spots are described. Figure 1 shows the schematic illustration of the ASO-X generator. ASO-X is using an inductive voltage adder technology and consists of three stages and total 6 capacitors, magnetic cores, field distortion spark gap switches and POS. The length, width and height of ASO-X generator are about 3.0 m, 1.8 m and 1.6 m, respectively. The capacitance of each capacitor is 3.2 pF and the total inductance of the generator is approximately 330 nH. The maximum charging voltage at each capacitor is 60 kV and the total stored energy is 35 kJ. The maximum output voltage is 180 kV and the peak current is 400 kA with 1.4 ps of the quarter period. In this experiment the charging volta...