Loading Circuit Coupled Magnetohydrodynamic Simulation of Sample Configurations in Isentropic Compression Experiments

Based on the 1-D elastic-plastic reactive hydrodynamic code Simplified Stretch Sin, a magnetohydrodynamic (MHD) version SSS/MHD has been developed. The new code is of multifield coupling, making use of the Resistance-Inductance-Capacitance circuit equations related to loading currents and others. To calculate MHD and circuit variables consistently and simultaneously, on the basis of Faraday's law, the relations between loading currents and magnetic flux in configuration cavities, variation in total magnetic flux and back electromotive force, and an iteration procedure are employed. The sample configurations in magnetically driven isentropic compression experiments (ICEs) here consist of parallel slabs and cavities, in which the step targets are a pair of slabs symmetrical to loading electrodes and of the same sample material but different in thickness. Self-consistent MHD and circuit calculations for ICE step targets of aluminum, tantalum, and plastic binder explosive is reported in this paper. The results agree with the measured ones well, including loading current profiles and velocity histories on samples' free surface or optics window interface. Since the input data for this code are geometric sizes, material parameters, and original circuit parameters only, its results are independent of measured or empirical data, and could be helpful in design and prediction of ICE or other experiments.