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Title: Models of radiation yield from wire array implosion at 1 MA Zebra generator

Abstract

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 kinetic 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 behindmore » 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

Authors:
 [1]
  1. Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)
Publication Date:
OSTI Identifier:
20782742
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 13; Journal Issue: 4; Other Information: DOI: 10.1063/1.2192754; (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; ALUMINIUM; ANALYTICAL SOLUTION; COUPLING; ELECTRON TEMPERATURE; EMISSION; EV RANGE; EXPLODING WIRES; IMPEDANCE; IMPLOSIONS; ION TEMPERATURE; KINETIC ENERGY; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; PERFORMANCE; PLASMA; PLASMA DENSITY; PLASMA HEATING; PLASMA SHEATH; PLASMA SIMULATION; RADIATION TRANSPORT; TEMPERATURE GRADIENTS; THERMALIZATION; YIELDS

Citation Formats

Esaulov, Andrey. Models of radiation yield from wire array implosion at 1 MA Zebra generator. United States: N. p., 2006. Web. doi:10.1063/1.2192754.
Esaulov, Andrey. Models of radiation yield from wire array implosion at 1 MA Zebra generator. United States. doi:10.1063/1.2192754.
Esaulov, Andrey. Sat . "Models of radiation yield from wire array implosion at 1 MA Zebra generator". United States. doi:10.1063/1.2192754.
@article{osti_20782742,
title = {Models of radiation yield from wire array implosion at 1 MA Zebra generator},
author = {Esaulov, Andrey},
abstractNote = {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 kinetic 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.},
doi = {10.1063/1.2192754},
journal = {Physics of Plasmas},
number = 4,
volume = 13,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}
  • K-shell radiation of Al and Mg and L-shell radiation of Mo from implosions of compact cylindrical wire arrays (CCWA) on the 1 MA UNR Zebra generator was studied. Specifically, radiation from implosions of 3 and 6 mm CCWA with (16-24) Al-5052 (95% Al and 5% Mg) and Al-5052 (97.5% Al and 2.5% Mg) and Mo wires was analyzed using the full set of diagnostics: PCD and current signals, and X-ray pinhole images and spectra. Previously developed non-LTE models were applied to model spatially resolved time integrated as well as time-gated spatially integrated spectra from Al, Mg, and Mo plasmas. Derivedmore » electron temperature and density spatial gradients as well as percentage of radiating mass were studied and compared. In addition, the novel Wire Dynamics Model (WDM) was used to analyze the implosion dynamics of compact wire array loads.« less
  • 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
  • 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 kinkmore » 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.« less
  • Abstract not provided.
  • Abstract not provided.