Abstract
Production of iron K-shell x-rays has been studied in a series of recent experiments on Z accelerator at Sandia. We present the results of 1-D RMHD numerical simulation of these experiments. Our simulations explicitly take into account detailed radiation hydro physics, and use a heuristic model to describe the 3-D effect of the outer-through-inner mass interpenetration and current splitting associated with it, which typically take place in the nested wire array implosions. The physical model of a two-temperature plasma includes electron and ion heat conduction, heat exchange between electrons and ions, magnetic field diffusion, Ohmic heating, radiation energy transport and losses. The radiation losses and the distribution of plasma ionization states are determined from the solution of the coupled equations of the nonstationary collisional-radiative model and radiation transport for spectral lines and continuum. We study the dependence of the radiation yields in the K- and L-lines of iron and the radiation pulsewidths on the masses and radii of the nested arrays, which were varied in the experiments on Z so that the implosion time was kept constant. Our results indicate that the observed yield dependence on mass/radius is probably a 1 -D effect, with radiative performance determined mainly by the stagnating load mass. For a high mass/small radius the yield is low because the eta parameter of the plasma is small-ions in the K-shell are few. For a low mass/large radius, the plasma density at stagnation is low, and it radiates a smaller fraction of its energy in all spectral ranges before bouncing back. We present the results of a similar modeling for a slighly different experimental configuration, with some mass added initially near the axis, as if more wires were initially placed there. Simulations predict some gain in the K-shell yield for this load configuration. Simulations done for the refurbished ZR machine predict very high iron K-shell yields-the increase is greater than the current-squared scaling would give-with an optimum radius extended to a larger value than on Z.
| Original language | English |
|---|---|
| Title of host publication | IEEE International Conference on Plasma Science |
| Pages | 293 |
| Number of pages | 1 |
| Publication status | Published - 2004 |
| Externally published | Yes |
| Event | IEEE Conference Record - Abstracts: The 31st IEEE International Conference on Plasma Science, ICOPS2004 - Baltimore, MD, United States Duration: 28 Jun 2004 → 1 Jul 2004 |
Other
| Other | IEEE Conference Record - Abstracts: The 31st IEEE International Conference on Plasma Science, ICOPS2004 |
|---|---|
| Country | United States |
| City | Baltimore, MD |
| Period | 28.6.04 → 1.7.04 |
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ASJC Scopus subject areas
- Condensed Matter Physics
Cite this
Modeling of the k-shell radiation production in stainless steel nested wire arrays on Z. / Oreshkin, V. I.; Velikovich, A. L.; Davis, J.; Coverdale, C. A.; Deeney, C.
IEEE International Conference on Plasma Science. 2004. p. 293 4P35.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Modeling of the k-shell radiation production in stainless steel nested wire arrays on Z
AU - Oreshkin, V. I.
AU - Velikovich, A. L.
AU - Davis, J.
AU - Coverdale, C. A.
AU - Deeney, C.
PY - 2004
Y1 - 2004
N2 - Production of iron K-shell x-rays has been studied in a series of recent experiments on Z accelerator at Sandia. We present the results of 1-D RMHD numerical simulation of these experiments. Our simulations explicitly take into account detailed radiation hydro physics, and use a heuristic model to describe the 3-D effect of the outer-through-inner mass interpenetration and current splitting associated with it, which typically take place in the nested wire array implosions. The physical model of a two-temperature plasma includes electron and ion heat conduction, heat exchange between electrons and ions, magnetic field diffusion, Ohmic heating, radiation energy transport and losses. The radiation losses and the distribution of plasma ionization states are determined from the solution of the coupled equations of the nonstationary collisional-radiative model and radiation transport for spectral lines and continuum. We study the dependence of the radiation yields in the K- and L-lines of iron and the radiation pulsewidths on the masses and radii of the nested arrays, which were varied in the experiments on Z so that the implosion time was kept constant. Our results indicate that the observed yield dependence on mass/radius is probably a 1 -D effect, with radiative performance determined mainly by the stagnating load mass. For a high mass/small radius the yield is low because the eta parameter of the plasma is small-ions in the K-shell are few. For a low mass/large radius, the plasma density at stagnation is low, and it radiates a smaller fraction of its energy in all spectral ranges before bouncing back. We present the results of a similar modeling for a slighly different experimental configuration, with some mass added initially near the axis, as if more wires were initially placed there. Simulations predict some gain in the K-shell yield for this load configuration. Simulations done for the refurbished ZR machine predict very high iron K-shell yields-the increase is greater than the current-squared scaling would give-with an optimum radius extended to a larger value than on Z.
AB - Production of iron K-shell x-rays has been studied in a series of recent experiments on Z accelerator at Sandia. We present the results of 1-D RMHD numerical simulation of these experiments. Our simulations explicitly take into account detailed radiation hydro physics, and use a heuristic model to describe the 3-D effect of the outer-through-inner mass interpenetration and current splitting associated with it, which typically take place in the nested wire array implosions. The physical model of a two-temperature plasma includes electron and ion heat conduction, heat exchange between electrons and ions, magnetic field diffusion, Ohmic heating, radiation energy transport and losses. The radiation losses and the distribution of plasma ionization states are determined from the solution of the coupled equations of the nonstationary collisional-radiative model and radiation transport for spectral lines and continuum. We study the dependence of the radiation yields in the K- and L-lines of iron and the radiation pulsewidths on the masses and radii of the nested arrays, which were varied in the experiments on Z so that the implosion time was kept constant. Our results indicate that the observed yield dependence on mass/radius is probably a 1 -D effect, with radiative performance determined mainly by the stagnating load mass. For a high mass/small radius the yield is low because the eta parameter of the plasma is small-ions in the K-shell are few. For a low mass/large radius, the plasma density at stagnation is low, and it radiates a smaller fraction of its energy in all spectral ranges before bouncing back. We present the results of a similar modeling for a slighly different experimental configuration, with some mass added initially near the axis, as if more wires were initially placed there. Simulations predict some gain in the K-shell yield for this load configuration. Simulations done for the refurbished ZR machine predict very high iron K-shell yields-the increase is greater than the current-squared scaling would give-with an optimum radius extended to a larger value than on Z.
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M3 - Conference contribution
AN - SCOPUS:13244295365
SP - 293
BT - IEEE International Conference on Plasma Science
ER -