Numerical studies of wire array Z-pinch x-ray source on the PTS facility

Abstract

The Z-pinch driven x-ray source is the combinations of the pulsed-power electrical energy source, transmission line, switch and the wire-array load. It has been proved by many experiments that the x-ray source produced by Z pinches has wide applications on inertial confinement fusion, high energy density science and experimental astrophysics. Full circuit model has been developed to simulate the discharge process of the Z-pinch driven x-ray source problem. Circuit model has been applied to each part of the combinations, and the full circuit model is constructed by connecting all the parts in series. Then the full circuit model is coupled with the radiation MHD model to simulate the electrical pulse transmissions and the implosions of the Z pinch plasmas. The influences of the circuit parameters and load parameters on the outputs were examined. Besides the loss current at the magnetically insulated transmission lines (MITL) in vacuum, the breakdown voltage and the inductance of the output switch are the most important. The appropriate reduction of the inductance of the output switch helps to get more powerful and faster electrical pulse. The Primary Test Stand (PTS) facility is the most powerful pulsed-power generator for Z pinch study in China. With the full circuit model and MHD model, the simulation of the propagation of electromagnetic wave pulse from the generator to the load is studied, the compression, amplification and the transmission of the pulse has been observed. The simulation results could show about the information of the pulse at some locations of the generator. The numerical results have been analyzed by comparing to the experiments and the simulation of the PSPICE software. As charged at a voltage of 60kV, the PTS facility delivers electrical pulse with power of 4TW and 880ns rise time to the intermediate storage of 24 modules, then the pulse compressed and added to about 20TW and 80ns at the water/vacuum insulator stack, and the x-ray power about 50TW with 4ns pulse width is produced by a Z pinch load of tungsten wire array with 600μg/cm line mass and 8MA load current.