2-DIMENSIONAL MAGNETOHYDRODYNAMIC MODELING OF CARBON-FIBER Z-PINCH EXPERIMENTS

A two-dimensional magneto-hydrodynamic simulation incorporating cold s tart conditions is used to explain the early phase of carbon fiber Z-p inch experiments. The rapid development of large scale, nonlnear m=0 p erturbations in the plasma corona is reproduced. X-ray bright spot for mation in the necks of the instability is followed by bright spot bifu rcation and fast axial motion. Bright spot bifurcation is found to be due to axial components of the jxB force and occurs off-axis due to th e presence of a residual core of unionized carbon. Artificial diagnost ic images are generated from the simulations data to allow direct comp arison with experimental x-ray imaging and laser probing diagnostics. The accurate reproduction of the experimental images provides confirma tion that the experimentally observed features are a repercussion of t he non-linear development-of the m=0 instability in an ionizing medium . (C) 1997 American Institute of Physics.