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Title: Investigation of regimes of wire array implosion on the 1 MA Zebra accelerator

Abstract

Implosion of wire arrays was investigated at the 1 MA Zebra accelerator by multiframe laser probing and gated x-ray self-emission diagnostics. Different regimes of implosion were observed in Al and Cu wire arrays. Implosion of Al loads with masses of 33-37 {mu}g/cm produces a dense pinch 1-1.5 mm in diameter. Strong instabilities are observed in the Z pinch at the time of stagnation. Implosion of ''overmassed'' loads produces a plasma column 3-4 mm in diameter with a core. The plasma column does not collapse during the x-ray pulse. The core of the plasma column is not subjected to the kink instability and transforms to a chain of dense spots in the later stage. Different regimes of implosion were observed in Al 8x15 {mu}m loads presumably due to variations in the current pulse and load conditions. Observed regimes are compared to three-dimensional hybrid simulation of ideal and nonideal magnetohydrodynamics modes of implosion.

Authors:
; ; ; ; ; ; ; ; ; ; ; ;  [1];  [2];  [2]
  1. University of Nevada, Reno, 5625 Fox Avenue, Reno, Nevada 89506 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20782460
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 13; Journal Issue: 1; Other Information: DOI: 10.1063/1.2163334; (c) 2006 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; ACCELERATORS; ALUMINIUM; COMPUTERIZED SIMULATION; COPPER; EXPLODING WIRES; IMPLOSIONS; KINK INSTABILITY; LASERS; MAGNETOHYDRODYNAMICS; PLASMA; PLASMA DIAGNOSTICS; PLASMA SIMULATION; PULSES; THREE-DIMENSIONAL CALCULATIONS; VARIATIONS; X RADIATION; X-RAY SOURCES

Citation Formats

Ivanov, V.V., Kantsyrev, V.L., Sotnikov, V.I., Fedin, D.A., Astanovitskiy, A. L., Le Galloudec, B., Nalajala, V., Shrestha, I., Cowan, T.E., Jones, B., Coverdale, C. A., Deeney, C., LePell, P.D., Sandia National Laboratories, Albuquerque, New Mexico 87110, and Ktech Corporation, Albuquerque, New Mexico 87123. Investigation of regimes of wire array implosion on the 1 MA Zebra accelerator. United States: N. p., 2006. Web. doi:10.1063/1.2163334.
Ivanov, V.V., Kantsyrev, V.L., Sotnikov, V.I., Fedin, D.A., Astanovitskiy, A. L., Le Galloudec, B., Nalajala, V., Shrestha, I., Cowan, T.E., Jones, B., Coverdale, C. A., Deeney, C., LePell, P.D., Sandia National Laboratories, Albuquerque, New Mexico 87110, & Ktech Corporation, Albuquerque, New Mexico 87123. Investigation of regimes of wire array implosion on the 1 MA Zebra accelerator. United States. doi:10.1063/1.2163334.
Ivanov, V.V., Kantsyrev, V.L., Sotnikov, V.I., Fedin, D.A., Astanovitskiy, A. L., Le Galloudec, B., Nalajala, V., Shrestha, I., Cowan, T.E., Jones, B., Coverdale, C. A., Deeney, C., LePell, P.D., Sandia National Laboratories, Albuquerque, New Mexico 87110, and Ktech Corporation, Albuquerque, New Mexico 87123. Sun . "Investigation of regimes of wire array implosion on the 1 MA Zebra accelerator". United States. doi:10.1063/1.2163334.
@article{osti_20782460,
title = {Investigation of regimes of wire array implosion on the 1 MA Zebra accelerator},
author = {Ivanov, V.V. and Kantsyrev, V.L. and Sotnikov, V.I. and Fedin, D.A. and Astanovitskiy, A. L. and Le Galloudec, B. and Nalajala, V. and Shrestha, I. and Cowan, T.E. and Jones, B. and Coverdale, C. A. and Deeney, C. and LePell, P.D. and Sandia National Laboratories, Albuquerque, New Mexico 87110 and Ktech Corporation, Albuquerque, New Mexico 87123},
abstractNote = {Implosion of wire arrays was investigated at the 1 MA Zebra accelerator by multiframe laser probing and gated x-ray self-emission diagnostics. Different regimes of implosion were observed in Al and Cu wire arrays. Implosion of Al loads with masses of 33-37 {mu}g/cm produces a dense pinch 1-1.5 mm in diameter. Strong instabilities are observed in the Z pinch at the time of stagnation. Implosion of ''overmassed'' loads produces a plasma column 3-4 mm in diameter with a core. The plasma column does not collapse during the x-ray pulse. The core of the plasma column is not subjected to the kink instability and transforms to a chain of dense spots in the later stage. Different regimes of implosion were observed in Al 8x15 {mu}m loads presumably due to variations in the current pulse and load conditions. Observed regimes are compared to three-dimensional hybrid simulation of ideal and nonideal magnetohydrodynamics modes of implosion.},
doi = {10.1063/1.2163334},
journal = {Physics of Plasmas},
number = 1,
volume = 13,
place = {United States},
year = {Sun Jan 15 00:00:00 EST 2006},
month = {Sun Jan 15 00:00:00 EST 2006}
}
  • Implosion of wire arrays was investigated at the 1 MA Zebra accelerator by multiframe laser probing and gated x-ray self-emission diagnostics. Different regimes of implosion were observed in Al and Cu wire arrays. Implosion of Al loads with masses of 33-37 {micro}g/cm produces a dense pinch 1-1.5 mm in diameter. Strong instabilities are observed in the Z pinch at the time of stagnation. Implosion of 'overmassed' loads produces a plasma column 3-4 mm in diameter with a core. The plasma column does not collapse during the x-ray pulse. The core of the plasma column is not subjected to the kinkmore » instability and transforms to a chain of dense spots in the later stage. Different regimes of implosion were observed in Al 8 x 15 {micro}m loads presumably due to variations in the current pulse and load conditions. Observed regimes are compared to three-dimensional hybrid simulation of ideal and nonideal magnetohydrodynamics modes of implosion.« less
  • The snowplow and thin shell models that have the analytical solutions in zero dimensions are linked with the ideal magnetohydrodynamic (MHD) and radiation MHD codes to calculate the radiation yield from the imploding wire array loads at 1 MA Zebra generator. Radiation MHD simulations show that the strong radiation cooling affects plasma dynamics at all stages of the implosion and drives plasma into the radiative collapse at the final stage of the implosion. Being applied to the implosion of an Al wire array with the mass per unit length 3.82 {mu}g/mm, these simulations show that the thermalization of the kineticmore » energy can be essentially completed when the radius of the imploding pinch shrinks below {approx}10 {mu}m. If we assume such a perfect compression, then the plasma energy gain will be 10 kJ with total radiation yield of about 5 kJ, while the emitted radiation spectrum will be blackbody-like with an equilibrium temperature of 200 eV. The only effective mechanism of energy coupling for the imploding plasma, driven by the magnetic piston, is the inductive work of the magnetic field due to the motional impedance. However, the mechanism of anomalous plasma heating, acting in the plasma fraction that was left behind the collapsing current sheath, can couple additional energy into the plasma and can explain the variety of radiation performance features. An adequate model of the radiation yield should consider the stagnating z pinch as an object with strong density and temperature gradients.« less
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