Development and test of the “Yingguang-1” program-discharged pulsed power device

Yingguang-1 is a multi-bank program-discharged pulsed power device for investigating the formation, confinement and instability of the high temperature and high density field reversed configuration (FRC) plasma injector in magnetized target fusion (MTF), which has been constructed at the Institute of Fluid Physics (IFP) in 2014. In this paper we will present the composition and the parameters of the Yingguang-1 device, and briefly describe the progress on the experiments of the FRC formation. In construction of the Yingguang-1 device, the rail gap switch with the peak current of 400 kA and the corresponding trigger system with the voltage greater than 200 kV and rise time less than 20 ns were firstly developed. Utilizing the mixture of 25% sulfur hexafluoride (SF6) and 75% nitrogen (N2) as the insulation gas, the switch could operate from 50 kV to 150 kV and the maximum offset of the start-up time would be less than 50 ns during repetitive test. By the high speed frame camera more than 5 discharged channels were observed in the switch. Experimental results of the pulsed power system show that the peak current/magnetic fields were 110 kA/0.3 T, 10 kA/1.2 T and 1.7 MA/3.4 T in the bias, mirror and -pinch circuit with the quarter cycle of 80 s, 700 s and 3.8 s when the charging voltage were set to 7 kV, 7 kV and 60 kV respectively. After the construction of Yingguang-1 device the preliminary experiments of the FRC target formation was conducted. With the H2 gas of 8.5 Pa, the plasma target of density 3.51016 cm-3, separatrix radius 4 cm, length 17 cm, average total temperature 200 eV and life time 3 s approximately equals to the half pulse width of the reversed field were obtained through the -pinch method when the bias, mirror, ionization and -pinch bank were charged to 5 kV, 5 kV, 55 kV and 45 kV respectively. The images from the end-on frame camera demonstrate the formation of FRC and agree with the results from the two dimension magneto hydrodynamics code (2D-MHD).