PPPS-2013: Microsecond ramp compression of a metallic liner driven by a shaped 5 MA current on the SPHINX machine

Summary form only given. SPHINX is a 6MA, 1-μs Linear Transformer Driver operated by the CEA Gramat (France) and primarily used for imploding Z-pinch loads for radiation effects studies. A method for performing magnetic ramp compression experiments, without modifying the generator operation scheme, is developed using a compact pulse shaping system. This system, a Dynamic Load Current Multiplier (DLCM), is inserted in vacuum between the convolute and the load. We present the overall experimental configuration chosen for these experiments, based on electrical and hydrodynamic simulations. Initial results obtained over a set of experiments on an aluminum cylindrical liner, ramp-compressed to a peak pressure of 230 kbar, are presented and analyzed. Detailed features of the electrical and Photonic Doppler Velocimetry (PDV) setups used to monitor and diagnose the ramp compression experiments are provided. Current profiles measured at various critical locations throughout the system, particularly the load current, are in good agreement with simulated current profiles. They enabled a comprehensive tracking of the current circulation and demonstrate adequate pulse shaping by the DLCM. Also, the liner inner free surface velocity measurements agree with the hydrocode results obtained using the measured load current as the input. The potential of the technique in terms of applications and achievable ramp pressure levels lies in the prospects for improving the DLCM efficiency through the use of a closing switch (currently under development) and optimizing the load dimensions.