Cylindrical liner Z-pinch experiments for fusion research and high-energy-density physics

Abstract

A gas-filled cylindrical liner z-pinch configuration has been used to drive convergent radiative shock waves into different gases at velocities of 20–50 km s−1. On application of the 1.4 MA, 240 ns rise-time current pulse produced by the Magpie generator at Imperial College London, a series of cylindrically convergent shock waves are sequentially launched into the gas-fill from the inner wall of the liner. This occurs without any bulk motion of the liner wall itself. The timing and trajectories of the shocks are used as a diagnostic tool for understanding the response of the liner z-pinch wall to a large pulsed current. This analysis provides useful data on the liner resistivity, and a means to test equation of state (EOS) and material strength models within MHD simulation codes. In addition to providing information on liner response, the convergent shocks are interesting to study in their own right. The shocks are strong enough for radiation transport to influence the shock wave structure. In particular, we see evidence for both radiative preheating of material ahead of the shockwaves and radiative cooling instabilities in the shocked gas. Some preliminary results from initial gas-filled liner experiments with an applied axial magnetic field are also discussed.

Inverse Liner Z-Pinch: An Experimental Pulsed Power Platform for Studying Radiative Shocks

“…This yielded a launch time of 187 ± 24 ns after the current start. These launch times are comparable to those seen in previous converging shock experiments [24] while velocities are slower by a factor of 2 (∼10 km/s instead of ∼20 km/s) primarily due to the increased mass density of the gas-fill. However, in contrast to the multiple shocks observed in converging shock experiments, only a single shock (ignoring edge effects) is observed in the experiments described in this paper.…”

“…It is possible to produce radiative shocks in laboratory experiments using lasers focused onto a pin embedded in a gas [9], a cluster gas [10]- [12], or a piston attached to a gas cell [13]- [21]. Radiative shocks have also been produced on pulsed power generators using imploding liners with an internal gas fill [22]- [24]. In these experiments, ∼1 MA of current was discharged through a gas-filled liner (a thin-walled metal tube).…”

Influence of atomic kinetics in the simulation of plasma microscopic properties and thermal instabilities for radiative bow shock experiments

“…The fitting of the RPL and these proposed criteria have been already used to predict the possibility of thermal instabilities in experiments of convergent radiative shocks in argon and neon produced in a cylindrical liner Z-pinch configuration [24] and also in experiments of blast waves launched in clusters of xenon [17,26,60]. In both cases, the results obtained theoretically were consistent with the experimental observations.…”

“…The first one is the analysis of the validity of LTE assumption in the calculation of average microscopic properties of argon plasmas in mass densities and electron temperatures ranging from 10 −6 to 10 −1 g cm −3 and from 1 to 100 eV, respectively. Argon is an element commonly used in laboratory astrophysics experiments on radiative shocks generated using either pulsed power devices [19,[21][22][23][24] or ultraintense lasers [17,[25][26][27][28][29][30], and the ranges of plasma conditions of these experiments fall within the ones before mentioned, hence, the interest of this study. For this analysis, we have made calculations assuming the plasma either in LTE and therefore using the Saha-Boltzmann (SB) equations, or in non-LTE (NLTE) in steady state, in which we have solved the rate equations implemented in our collisional-radiative model.…”

Microscopic properties of xenon plasmas for density and temperature regimes of laboratory astrophysics experiments on radiative shocks

“…We have already used our fitting of the RPL and these criteria to predict the possibility of isobaric radiative cooling instabilities experiments of convergent radiative shocks in argon and neon generated in a cylindrical liner Z-pinch configuration, obtaining results that are consistent with the experimental observations [71].…”