Progress on high current pulse transmission based on the Primary Test Stand

High efficiency pulse current transmission is critical important for inertial confinement fusion (ICF), dynamic material property research and other high energy density physics experiments, in which current density in several MA/cm will achieved on the electrode surface near the load. Independent on power generation, high current pulse transmission to load has to deal with structural transition in transmission line, massive electrons/ions insulation, ~MA/cm current density, megagauss (MG) magnetic field and its diffuse into conductor. The current loss across transition and the penetration of MG magnetic fields into conductors may cause anode-cathode gap closure, and even transmission failure. In order to understand the pulse transmission property in MA/cm range, two types of experiments were carried out on the Primary Test Stand. In the stainless steel electrode transmission experiments, the expansion velocity of conductor at several MG magnetic field was recorded with displacement interferometer system and the evolution process of dense plasma were recorded by shadowgraphy system. One dimensional magneto-hydrodynamics (MHD) simulations to the experiments were carried out and a threshold magnetic field of 3.3 MG for thermal plasma formation was inferred for stainless steel. In the coaxial-conical transition experiment, current transmission efficiency under MA/cm current density was derived for different states. In this paper, the pulsed power platform, the experimental designs and results will be presented.