Characterization of energy flow and instability development in two-dimensional simulations of hollow {ital z} pinches
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
- University of New Mexico, Albuquerque, New Mexico 87131 (United States)
A two-dimensional (2-D) Eulerian Radiation-Magnetohydrodynamic (RMHD) code has been used to simulate imploding {ital z} pinches for three experiments fielded on the Los Alamos Pegasus II capacitor bank [J. C. Cochrane {ital et al.}, {ital Dense Z-Pinches, Third International Conference, London, United Kingdom 1993} (American Institute of Physics, New York, 1994), p. 381] and the Sandia Saturn accelerator [R. B. Spielman {ital et al.}, {ital Dense Z-Pinches, Second International Conference, Laguna Beach, 1989} (American Institute of Physics, New York, 1989), p. 3] and {ital Z} accelerator [R. B. Spielman {ital et al.}, Phys. Plasmas {bold 5}, 2105 (1998)]. These simulations match the experimental results closely and illustrate how the code results may be used to track the flow of energy in the simulation and account for the amount of total radiated energy. The differences between the calculated radiated energy and power in 2-D simulations and those from zero-dimensional (0-D) and one-dimensional (1-D) Lagrangian simulations (which typically underpredict the total radiated energy and overpredict power) are due to the radially extended nature of the plasma shell, an effect which arises from the presence of magnetically driven Rayleigh{endash}Taylor instabilities. The magnetic Rayleigh{endash}Taylor instabilities differ substantially from hydrodynamically driven instabilities and typical measures of instability development such as {ital e}-folding times and mixing layer thickness are inapplicable or of limited value. A new measure of global instability development is introduced, tied to the imploding plasma mass, termed {open_quotes}fractional involved mass.{close_quotes} Examples of this quantity are shown for the three experiments along with a discussion of the applicability of this measure. {copyright} {ital 1998 American Institute of Physics.}
- OSTI ID:
- 641528
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 9 Vol. 5; ISSN PHPAEN; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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