MHD modeling of conductors at ultrahigh current density

In conjunction with ongoing high-current experiments on Sandia National Lab oratories' Z accelerator (Albuquerque, NM) we have revisited a problem firs t described in detail by Heinz Knoepfel [1], Unlike the l-Tesla MITL's of p ulsed power accelerators used to produce intense particle beams, Z's disk, transmission line (downstream of the current addition) is in a 100-1200-Tes la regime; so its conductors cannot be modeled simply as static infinite co nductivity boundaries. Using the MHD code [2], [3], [17] MACH2 we have been investigating the conductor hydrodynamics, characterizing the joule heatin g, magnetic field diffusion, and material deformation, pressure, and veloci ty over a range of current densities, current rise-times, and conductor mat erials. The three purposes of this work are 1) to quantify power flow losse s owing to ultrahigh magnetic fields, 2) to model the response of VISAR [4] , [18], [19] diagnostic samples in various configurations on Z, and 3) to i ncorporate the most appropriate equation of state and conductivity models i nto our magnetohydrodynamics (MHD) computations. Certain features are stron gly dependent on the details of the conductivity model.