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Title: Magnetic Rayleigh-Taylor instability mitigation and efficient radiation production in gas puff Z-pinch implosions

Abstract

Large radius Z-pinches are inherently susceptible to the magnetic Rayleigh-Taylor (RT) instability because of their relatively long acceleration path. This has been reflected in a significant reduction of the argon K-shell yield as was observed when the diameter of the load was increased from 2.5 to >4 cm. Recently, an approach was demonstrated to overcome the challenge with a structured gas puff load that mitigates the RT instability, enhances the energy coupling, and leads to a high compression, high yield Z-pinch. The novel load consists of a 'pusher', outer region plasma that carries the current and couples energy from the driver, a 'stabilizer', inner region plasma that mitigates the RT growth, and a ''radiator,'' high-density center jet plasma that is heated and compressed to radiate. In 3.5-MA, 200-ns, 12-cm initial diameter implosions, the Ar K-shell yield has increased by a factor of 2, to 21 kJ, matching the yields obtained on the same accelerator with 100-ns, 2.5-cm-diam implosions. Further tests of such structured Ar gas load on {approx}6 MA, 200-ns accelerators have achieved >80 kJ. From laser diagnostics and measurements of the K-shell and extreme ultraviolet emission, initial gas distribution and implosion trajectories were obtained, illustrating the RT suppression andmore » stabilization of the imploding plasma, and identifying the radiation source region in a structured gas puff load. Magnetohydrodynamic simulations, started from actual initial density profiles, reproduce many features of the measurements both qualitatively and quantitatively.« less

Authors:
; ; ; ; ; ; ; ;  [1];  [2];  [2]
  1. L-3 Pulse Sciences, San Leandro, California 94577 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20975065
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2436468; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCELERATION; ACCELERATORS; ARGON; COMPRESSION; CURRENTS; EXTREME ULTRAVIOLET RADIATION; IMPLOSIONS; K SHELL; MAGNETOHYDRODYNAMICS; PLASMA; PLASMA DENSITY; PLASMA DIAGNOSTICS; PLASMA GUNS; PLASMA JETS; PLASMA SIMULATION; RADIATION SOURCES; RAYLEIGH-TAYLOR INSTABILITY

Citation Formats

Sze, H., Levine, J. S., Banister, J., Failor, B. H., Qi, N., Steen, P., Velikovich, A. L., Davis, J., Wilson, A., Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, and Avonia Inc., San Diego, California 92130. Magnetic Rayleigh-Taylor instability mitigation and efficient radiation production in gas puff Z-pinch implosions. United States: N. p., 2007. Web. doi:10.1063/1.2436468.
Sze, H., Levine, J. S., Banister, J., Failor, B. H., Qi, N., Steen, P., Velikovich, A. L., Davis, J., Wilson, A., Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, & Avonia Inc., San Diego, California 92130. Magnetic Rayleigh-Taylor instability mitigation and efficient radiation production in gas puff Z-pinch implosions. United States. doi:10.1063/1.2436468.
Sze, H., Levine, J. S., Banister, J., Failor, B. H., Qi, N., Steen, P., Velikovich, A. L., Davis, J., Wilson, A., Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, and Avonia Inc., San Diego, California 92130. Tue . "Magnetic Rayleigh-Taylor instability mitigation and efficient radiation production in gas puff Z-pinch implosions". United States. doi:10.1063/1.2436468.
@article{osti_20975065,
title = {Magnetic Rayleigh-Taylor instability mitigation and efficient radiation production in gas puff Z-pinch implosions},
author = {Sze, H. and Levine, J. S. and Banister, J. and Failor, B. H. and Qi, N. and Steen, P. and Velikovich, A. L. and Davis, J. and Wilson, A. and Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375 and Avonia Inc., San Diego, California 92130},
abstractNote = {Large radius Z-pinches are inherently susceptible to the magnetic Rayleigh-Taylor (RT) instability because of their relatively long acceleration path. This has been reflected in a significant reduction of the argon K-shell yield as was observed when the diameter of the load was increased from 2.5 to >4 cm. Recently, an approach was demonstrated to overcome the challenge with a structured gas puff load that mitigates the RT instability, enhances the energy coupling, and leads to a high compression, high yield Z-pinch. The novel load consists of a 'pusher', outer region plasma that carries the current and couples energy from the driver, a 'stabilizer', inner region plasma that mitigates the RT growth, and a ''radiator,'' high-density center jet plasma that is heated and compressed to radiate. In 3.5-MA, 200-ns, 12-cm initial diameter implosions, the Ar K-shell yield has increased by a factor of 2, to 21 kJ, matching the yields obtained on the same accelerator with 100-ns, 2.5-cm-diam implosions. Further tests of such structured Ar gas load on {approx}6 MA, 200-ns accelerators have achieved >80 kJ. From laser diagnostics and measurements of the K-shell and extreme ultraviolet emission, initial gas distribution and implosion trajectories were obtained, illustrating the RT suppression and stabilization of the imploding plasma, and identifying the radiation source region in a structured gas puff load. Magnetohydrodynamic simulations, started from actual initial density profiles, reproduce many features of the measurements both qualitatively and quantitatively.},
doi = {10.1063/1.2436468},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}