Deformable contact liner implosion performed with 8 cm diameter electrode apertures

Summary form only given. We present experimental data indicating the feasibility of using a varying thickness in a long cylindrical solid liner, driven as a Z-pinch, to achieve factor /spl sim/17 cylindrical convergence, while using large aperture electrodes. The Al liner was 30 cm long, with 9.78 cm inner diameter for its full length, 10.0 cm outer diameter for the central 18 cm of its length, and outer diameter increased linearly to 10.2 cm at 1 cm from either electrode, and to 11 cm at electrode contacts. The two electrodes had 8 cm diameter holes or apertures, to allow injection of field reversed configurations (FRCs) in proposed future experiments on magnetized target fusion (MTF). 2D-MHD simulations as well as flash radiography and axial view fast optical photography indicate that this varying thickness results in a deforming, nearly non-sliding, liner-electrode contact. The Z-pinch geometry discharge was driven by the AFRL Shiva Star 1300 microfarad capacitor bank, charged to 84 kilovolts, with /spl sim/44 nanoHenry initial inductance, sub-milliohm external resistance, plus a safety fuse as described. The current history was similar to that for similar, uniform thickness long liner implosions with the more traditional sliding liner-electrode contact, reported. The current exceeded 11 megamps with /spl sim/10 microsecond risetime. The implosion time was 22.5 microseconds. The inner surface implosion velocity exceeded 0.5 cm/microsecond, and kinetic energy was /spl sim/1 megajoule.