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Title: Radiative precursors driven by converging blast waves in noble gases

A detailed study of the radiative precursor that develops ahead of converging blast waves in gas-filled cylindrical liner z-pinch experiments is presented. The experiment is capable of magnetically driving 20 km s{sup −1} blast waves through gases of densities of the order 10{sup −5} g cm{sup −3} (see Burdiak et al. [High Energy Density Phys. 9(1), 52–62 (2013)] for a thorough description). Data were collected for Ne, Ar, and Xe gas-fills. The geometry of the setup allows a determination of the plasma parameters both in the precursor and across the shock, along a nominally uniform line of sight that is perpendicular to the propagation of the shock waves. Radiation from the shock was able to excite NeI, ArII, and XeII/XeIII precursor spectral features. It is shown that the combination of interferometry and optical spectroscopy data is inconsistent with upstream plasmas being in LTE. Specifically, electron density gradients do not correspond to any apparent temperature change in the emission spectra. Experimental data are compared to 1D radiation hydrodynamics HELIOS-CR simulations and to PrismSPECT atomic physics calculations to assist in a physical interpretation of the observations. We show that upstream plasma is likely in the process of being radiatively heated and that themore » emission from a small percentage of ionised atoms within a cool background plasma dominates the emission spectra. Experiments were carried out on the MAGPIE and COBRA pulsed-power facilities at Imperial College London and Cornell University, respectively.« less
Authors:
; ; ; ; ; ; ; ; ; ; ; ; ;  [1] ;  [2] ; ; ; ; ;  [3] more »; « less
  1. Blackett Laboratory, Imperial College London SW7 2BW (United Kingdom)
  2. Atomic Weapons Establishment, Aldermaston RG7 4PR (United Kingdom)
  3. Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853 (United States)
Publication Date:
OSTI Identifier:
22251959
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 3; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ATOMIC PHYSICS; CYLINDRICAL CONFIGURATION; ELECTRON DENSITY; EMISSION SPECTRA; HYDRODYNAMICS; LTE; PLASMA; RARE GASES; SHOCK WAVES