A short-pulse mode for the SPHINX LTD Z-pinch driver

The SPHINX machine is a 6MA, 1 $\mu$s, LTD Z-pinch driver at CEA Gramat (France) and primarily used for studying radiation effects. Different power amplification concepts were examined in order to reduce the current rise time without modifying the generator discharge scheme, including the Dynamic Load Current Multiplier (DLCM) proposed by Chuvatin [1]. A DLCM device, capable of shaping the current pulse without reducing the rise time, was developed at CEA. This device proved valuable for isentropic compression experiments in cylindrical geometry [2]. Recently, we achieved a short pulse operation mode by inserting a vacuum closing switch between the DLCM and the load. The current rise time was reduced to $\sim $300 ns. We explored the use of a reduced-height wire array for the Dynamic Flux Extruder in order to improve the wire array compression rate and increase the efficiency of the current transfer to the load. These developments are presented. Potential benefits of these developments for future Z pinch experiments are discussed.\\[4pt] [1] A.S. Chuvatin, ``Dynamic Current Multiplier''; 14$^{th}$ Symposium on High Current Electronics, Tomsk, Russia, pp 232-235 (2006).\\[0pt] [2] T. d'Almeida \textit{et al,} \textit{Phys. Plasmas}, \textbf{20}, 092512-1 092512-16 (2013).