Enhancing the x-ray output of a single-wire explosion with a gas-puff based plasma opening switch

Abstract

We present experiments performed on the 1 MA COBRA generator using a low density, annular, gas-puff z-pinch implosion as an opening switch to rapidly transfer a current pulse into a single metal wire on axis. This gas-puff on axial wire configuration was studied for its promise as an opening switch and as a means of enhancing the x-ray output of the wire. We demonstrate that current can be switched from the gas-puff plasma into the wire, and that the timing of the switch can be controlled by the gas-puff plenum backing pressure. X-ray detector measurements indicate that for low plenum pressure Kr or Xe shots with a copper wire, this configuration can offer a significant enhancement in the peak intensity and temporal distribution of radiation in the 1–10 keV range.

Observation of fast current redistribution in an imploding plasma column

“…Specifically, we measure that during stagnation the current transitions out of the SP and into a low density plasma (LDP), residing at much larger radii, while the SP continues to implode. This phenomenon might be connected to the previous observations of low current in the SP of Zpinches [11,20,[24][25][26], and might be common to various pulsed-power systems, including those of lower density plasmas [11], such as plasma switches [12][13][14] and high power transmission lines [15,16].…”

“…The force exerted on a plasma by a current and by its associated magnetic field governs various processes in space and laboratory plasmas [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. This force is largely affected by the distribution of the current in the plasma.…”

“…The fast current-escape from the SP found here might be related to the low current observed at the stagnation of Z-pinches [11,20,[24][25][26], however further mechanisms for this phenomenon of low current in the SP have to be investigated. The fast current redistribution might also bear relevance to general pulsed-power systems, such as plasma switches [12][13][14] or transmission lines [15,16]. In these systems, undesired plasmas of various properties can be produced due to different sources, such as electrodes [15,16], instabilities [41,42], evaporation in solid loads [43], boundary layers in gas loads [30], and unimploded plasma in Z-pinches [23].…”

Simulation and experimental results of plasma opening switch operation with inductive and electron beam diode loads in different plasma regimes

“…Class of tera/peta watt devices based on pulse compression technology with inductive storage as an intermediate store and plasma opening switch (POS) has been used for many applications, including flash x-ray radiation sources [1,2], electron beam generators [3], accelerators [4], etc, and its research is continuing since more than four decades from the first POS is implemented [5]. POS is a coaxial structure with a gap between the cathode and anode.…”