MHD modeling of ATLAS experiments to study transverse shear interface interactions

Summary form only given. The transverse shear established at the interface of two solids moving at differential velocities on the order of the sound speed is being studied in experiments on the ATLAS capacitor bank at Los Alamos, beginning in August 2001. The ATLAS bank has finished certification tests and has demonstrated peak currents of 27.5 MA with a 5 microsecond risetime into an inductive load. One- and two-dimensional MHD calculations have been performed in support of these "friction-like" ATLAS experiments. Current flowing along the outer surface of a thick aluminum liner, roughly 8 mm thick, accelerates the solid liner to velocities /spl sim/1 km/s. This cylindrically imploding liner then impacts a target assembly, composed of alternating regions of high and low density materials. The different shock speeds in the two materials leads to a differential velocity along the interface. Shock heating, elastic-plastic flow, and stress transport are included in the calculations. Material strength properties are treated with a Steinburg-Guinan model. Various design configurations for the Atlas experiments are now being considered and will be presented. Detailed comparisons between data and calculations from smaller scale experiments on the PEGASUS capacitor bank will be presented.