Application of 2-D simulations to hollow Z-pinch implosions
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- Sandia National Laboratory, Albuquerque, New Mexico 87185 (United States)
- University of New Mexico, Albuquerque, New Mexico 87131 (United States)
The application of simulations of z-pinch implosions should have at least two goals: first, to properly model the most important physical processes occurring in the pinch allowing for a better understanding of the experiments and second, provide a design capability for future experiments. Beginning with experiments fielded at Los Alamos on the Pegasus I and Pegasus II capacitor banks, we have developed a methodology for simulating hollow z-pinches in two dimensions which has reproduced important features of the measured experimental current drive, spectrum, radiation pulse shape, peak power and total radiated energy (1,2,3). This methodology employs essentially one free parameter, the initial level of the random density perturbations imposed at the beginning of the 2-D simulation, but in general no adjustments to other parameters (such as the resistivity) are required (1). Limitations in the use of this approach include the use of the 3-T, gray diffusion treatment of radiation and the fact that the initial perturbation conditions are not known {ital a priori}. Nonetheless, the approach has been successful in reproducing important experimental features of such implosions over a wide variety of timescales (tens of nanoseconds to microseconds), current drives (3 to 16 MA), masses (submilligram to tens of milligrams), initial radii ({lt}1cm to 5 cm), materials (Al and W) and initial configurations (thin foils and wire arrays with 40 to 240 wires). Currently we are applying this capability to the analysis of recent Saturn and PBFA-Z experiments (4,5). The code results provide insight into the nature of the pinch plasma prior to arrival on-axis, during thermalization and development after peak pinch time. Among other things, the simulation results provide an explanation for the production of larger amounts of radiated energy than would be expected from a simple slug-model kinetic energy analysis and the appearance of multiple peaks in the radiation power. The 2-D modeling has also been applied to the analysis of Saturn {open_quotes}dynamic hohlraum{close_quotes} experiments and is being used in the design of this and other Z-Pinch applications on PBFA-Z. {copyright} {ital 1997 American Institute of Physics.}
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 649318
- Report Number(s):
- CONF-9705120-; ISSN 0094-243X; TRN: 98:009634
- Journal Information:
- AIP Conference Proceedings, Vol. 409, Issue 1; Conference: 4. international conference on dense Z-pinches, Vancouver (Canada), 28-31 May 1997; Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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