Long implosion time tungsten wire array Z pinches on the Saturn generator

Recent success on the Saturn [C. Deeney , Phys. Rev. E 56, 5945 (1997)] and Z [R. B. Spielman , Phys. Plasmas 5, 2105 (1998)] accelerators at Sandia N ational Laboratories have demonstrated the ability to scale Z-pinch paramet ers to increasingly larger current pulsed power facilities. Next generation machines will require even larger currents (> 20 MA), placing further dema nds on pulsed power technology. To this end, experiments have been carried out on Saturn operating in a long pulse mode, investigating the potential o f lower voltages and longer implosion times while still maintaining pinch f idelity. High wire number, 25 mm diam tungsten arrays were imploded with im plosion times ranging from 130 to 240 ns. The results were comparable to th ose observed in the Saturn short pulse mode, with rise times on the order o f 4.5-6.5 ns. Experimental data will be presented, along with two-dimension al radiation magnetohydrodynamic simulations used to explain and reproduce the experiment. (C) 2000 American Institute of Physics. [S1070- 664X(00)043 07-X].