Two-dimensional modeling of x-ray output from switched foil implosions on Procyon

Physics of Plasmas

Volumn 3, Issue 9, 1996, Pages 3448-3468

  Bowers, R L ^a   Nakafuji, G ^a   Greene, A E ^a   McLenithan, K D ^a   Peterson, D L ^a   Roderick, N F ^a,b  

^a LOS ALAMOS NATIONAL LABORATORY   (United States)

^b University of NewMexico   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0009749597     PISSN: 1070664X     EISSN: None     Source Type: Journal    
DOI: 10.1063/1.871594     Document Type: Article

References (25)

1. D. L. Peterson, R. L. Bowers, J. H. Brownell, A. E. Greene, K. D. McLenithan, T. A. Oliphant, N. F. Roderick, and A. J. Scannapieco, Phys. Plasmas 3, 268 (1996); R. L. Bowers, J. H. Brownell, A. E. Greene, H. Kruse, H. Oona, and D. L. Peterson, in Megagauss Magnetic Field Generation and Pulsed Power Applications, edited by M. Cowan and R. B. Speilman (Nova, New York, 1994), p. 777; H. Oona, R. L. Bowers, D. L. Peterson, J. C. Cochrane, and J. S. Ladish, ibid., p. 889.
2. D. L. Peterson, R. L. Bowers, J. H. Brownell, A. E. Greene, K. D. McLenithan, T. A. Oliphant, N. F. Roderick, and A. J. Scannapieco, Phys. Plasmas 3, 268 (1996); R. L. Bowers, J. H. Brownell, A. E. Greene, H. Kruse, H. Oona, and D. L. Peterson, in Megagauss Magnetic Field Generation and Pulsed Power Applications, edited by M. Cowan and R. B. Speilman (Nova, New York, 1994), p. 777; H. Oona, R. L. Bowers, D. L. Peterson, J. C. Cochrane, and J. S. Ladish, ibid., p. 889.
3. D. L. Peterson, R. L. Bowers, J. H. Brownell, A. E. Greene, K. D. McLenithan, T. A. Oliphant, N. F. Roderick, and A. J. Scannapieco, Phys. Plasmas 3, 268 (1996); R. L. Bowers, J. H. Brownell, A. E. Greene, H. Kruse, H. Oona, and D. L. Peterson, in Megagauss Magnetic Field Generation and Pulsed Power Applications, edited by M. Cowan and R. B. Speilman (Nova, New York, 1994), p. 777; H. Oona, R. L. Bowers, D. L. Peterson, J. C. Cochrane, and J. S. Ladish, ibid., p. 889.
4. W. Matuska, R. L. Bowers, J. H. Brownell, H. Lee, C. M. Lund, D. L. Peterson, and N. F. Roderick, Phys. Plasmas 3, 1415 (1996).
5. J. H. Goforth, B. G. Anderson, W. E. Anderson, D. E. Bartram, J. F. Benage, R. L. Bowers, J. H. Brownell, C. E. Findley, C. M. Fowler, G. J. Heltne, D. H. Herrera, T. J. Herrera, M. Y. Hockaday, G. Idzorak, J. C. King, I. R. Lindemuth, E. A. Lopez, S. P. Marsh, E. C. Martinez, W. Matuska, G. T. Nakafuji, M. C. Thompson, H. Oona, D. L. Peterson, R. E. Reinovsky, M. Rich, J. S. Shlachter, K. D. Sowder, J. L. Stokes, L. J. Tabaka, D. T. Torres, P. J. Turchi, L. R. Veeser, B. J. Warthen, M. I. Yapuncich, and W. D. Zerwekh, in Proceedings of the Tenth IEEE Pulsed Power Conference, July 1995, Albuquerque (Institute of Electrical Engineers, Piscataway, NJ, 1995).
6. J. H. Degnan, W. L. Baker, K. E. Hackett, D. J. Hall, J. L. Holmes, J. B. Kriebel, D. W. Price, R. E. Reinovsky, J. D. Graham, E. A. Lopez, M. L. Alme, G. Bird, C. N. Boyer, S. K. Coffey, D. Come, J. F. Davis III, S. W. Seiler, and P. J. Turchi, IEEE Trans. Plasma Sci. PS-15, 760 (1987); J. Buff, M. H. Frese, A. J. Giancola, R. E. Peterkin, Jr., and N. F. Roderick, ibid. PS-15, 766 (1987).
7. J. H. Degnan, W. L. Baker, K. E. Hackett, D. J. Hall, J. L. Holmes, J. B. Kriebel, D. W. Price, R. E. Reinovsky, J. D. Graham, E. A. Lopez, M. L. Alme, G. Bird, C. N. Boyer, S. K. Coffey, D. Come, J. F. Davis III, S. W. Seiler, and P. J. Turchi, IEEE Trans. Plasma Sci. PS-15, 760 (1987); J. Buff, M. H. Frese, A. J. Giancola, R. E. Peterkin, Jr., and N. F. Roderick, ibid. PS-15, 766 (1987).
8. P. J. Turchi, Opening Switches, edited by A. Guenther, M. Kristiansen, and T. Martin (Plenum, New York, 1987), p. 191.
9. J. H. Goforth, H. Oona, A. E. Greene, D. H. Herrera, D. L. Peterson, B. G. Anderson, W. E. Anderson, D. E. Bartram, J. H. Brownell, R. L. Bowers, R. E. Chrien, J. C. Cochrane, C. E. Findley, M. F. Fowler, O. F. Garcia, M. L. Hodgdon, J. C. King, I. R. Lindemuth, C. M. Lund, S. P. Marsh, T. Oliphant, J. V. Parker, R. E. Reinovsky, N. F. Roderick, J. S. Shlachter, L. J. Tabaka, D. T. Torres, P. J. Turchi, L. R. Veeser, B. J. Warthen, D. L. Weiss and F. J. Wysocki, Proceedings of the Ninth IEEE International Pulsed Power Conference, Albuquerque, N.M., June 1993, edited by K. Prestwich and W. Baker (Institute of Electrical Engineers, Piscataway, NJ, 1993), p. 36.
10. See National Technical Information Service Document No. NTIS DE94-011699 (J. D. Johnson, "SESAME Data Base"). Copies may be ordered from the national Technical Information Service, Springfield, Virginia 22161.
11. See National Technical Information Service document No. NTIS PB92-206168 (J. Brownell, J. Parker, R. Bartsch, J. Benage, R. Bowers, J. Cochrane, P. Forman, J. Goforth, A. Greene, H. Kruse, J. Ladish, H. Oona, D. Peterson, R. Reinovsky, N. Roderick, J. Trainor, P. Turchi, "The Los Alamos Foil Implosion Project," Proceedings of the 9th International Conference on High-Power Particle Beams, edited by D. Mosher and G. Cooperstein, p. 175, 1992). Copies may be ordered from the National Technical Information Service, Springfield, VA 22151.
12. The motivation for going to a mass graded foil in place of the conventional wire array was the desire to have an initial configuration that was cylindrical rather than three-dimensional. Clearly the presence of initial, random perturbations in the foil may negate most of the potential gain in chis approach.
13. The primary role of the barrier film is to prevent current from moving ahead of the switch prior to assembly, and to supply a temporary inertial tamping of the conducting plasma during the early stages of motion down the coaxial barrel. Calculations in which the barrier film initially occupied three zones in the axial direction and only one zone give essentially the same results.
14. Variations in axial thickness were carried out at a fixed mass of 130 mg. In each model the axial center of the conducting plasma was initially located 0.6 cm behind the barrier film.
15. A perturbation has also developed along the outer electrode, but it is of much smaller amplitude and does not significantly affect the evolution of the switch plasma. 13 Axial positions are measured with respect to the initial position of the graded aluminum foil.
16. This process, which we call a link, is accomplished by reading data from one computational grid and applying it as initial conditions to a newly defined computational grid. Whenever interpolation on physical variables is required, it is done in such a way as to conserve mass, momentum, internal and kinetic energy, and magnetic flux.
17. As demonstrated in Ref. 1, the backside of a magnetically imploding plasma is Rayleigh-Taylor unstable.
18. Background plasma can be expected to a rise from several sources, including radiatively induced ablation of electrode surfaces, poor initiation of the switch plasma, contaminants in the pulsed power system, and as a result of sparking and arcing at joints.
19. H. Oona, R. L. Bowers, D. L. Peterson, C. Findley, J. C. Cochrane, and J. S. Ladish, in Megagauss Magnetic Field Generation and Pulsed Power Applications, edited by M. Cowan and R. B. Spielman (Nova, New York, 1994), p. 889.
20. Low density background plasma carries magnetic flux from the switch to the load during switching. As this plasma stagnates in the corners formed by the load plasma and the electrodes it compresses on a time scale that is small compared with the resistive time scale. This process amplifies the local magnetic field.
21. T. W. Hussey, N. F. Roderick, and D. A. Kloc, J. Appl. Phys. 51, 1452 (1980).
22. The graded foils used on Procyon contain a significant amount of oxygen, and thus the actual opacity is expected to be as much as an order of magnitude greater than for pure aluminum.
23. A relative time difference in the implosion histories of the switched and ideal models results because the calculation of the PFS predicts that current is delivered to the load later than was observed in the experiment. For this reason the implosion in Fig. 18 begins about 0.5 μs earlier than in Fig. 7, for example. The difference in relative timing is believed to be due to details of how the switch opens, as well as on the background plasma density during switching.
24. A more systematic analysis of these features will be discussed elsewhere.
25. -1) mode in the spectrum. This would arise from catenary distortion of the load plasma, or from ideal magnetoacoustic switching into a cylindrical load. This mode does not arise from the form of the Fourier transform assumed in Eq. (1).