J. Quant. Spectrosc. Radiat. Transfer Vol. 44, No. 5/6, pp. 471-484, 1990 0022-4073/90 $3.00 + 0.00 Printed in Great Britain Pergamon Press plc ALUMINUM WIRE ARRAY IMPLOSIONS: COMPARISON OF EXPERIMENTS AND SIMULATION J. L. Giuliani, Jr. and J. E. Rogerson Radiation Hydrodynamics Branch Plasma Physics Division Naval Research Laboratory Washington, DC 20375 C. Deeney, T. Nash, R. R. Prasad, and M. Krishnan* Physics International Company 2700 Merced St., San Leandro, CA 94577 Abstract - A series of aluminum wire array implosions with nearly equal line density have been performed on the DOUBLE EAGLE pulse power generator. The measured implosion times, minimum radii, total radiative yields, K-shell yields, and K-shell pulse widths are compared against radiation-hydromagnetic simulations. The simulations treat the plasma as a uniform shell of finite thickness and include a circuit model for the generator. A short circuit and an enhanced resistivity are added to the simulation models in order to improve the agreement with experimental data. In general the final results are encouraging, but indicate that the present state of simulations is short of providing an accurate predictive capability. 1. INTRODUCTION The use of wire arrays to create x-radiation from a pinch driven by a pulse power generator was initially proposed over a decade ago by Stallings, Nielsen, and Schneider. I They noted the advantage of cylindrical wire array loads over single wire loads lies in the improved energy coupling between the generator and the imploding array. The improved coupling leads in turn to an enhancement of the keV radiative yield.2 The implosion prior to assembly on axis has often been modeled by treating the array as a pressureless, thin, cylindrical shell and combining the equation of motion with a circuit model for the generator. 3'4 Observations of the implosion time from streak camera photographs have partially verified the simple shell model.5,6 Once the plasma assembles on axis, the simple model breaks down because of the lack of an energy equation. To predict emergent spectra, one must go beyond the simple model and include the hydromagnetics of a finite sized plasma, the ionization dynamics of the plasma, and the radiation transport. The importance of the last process has been noted for gas puffs7'8, and some comparisons between the calculated and observed radiation have been made for argon, xenon, and krypton gas puff implosions on specific generators. 9'10 For wire arrays, a detailed comparison has not been presented in the literature. * Present address: Science Research Lab., 1150 Bellena Blvd., Alameda, Calif. 471