Two-dimensional magneto-hydrodynamic modeling of carbon fiber Z-pinch experiments

A two-dimensional magneto-hydrodynamic simulation incorporating cold start conditions is used to explain the early phase of carbon fiber Z-pinch experiments. The rapid development of large scale, nonlnear m=0 perturbations in the plasma corona is reproduced. X-ray bright spot formation in the necks of the instability is followed by bright spot bifurcation 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 the presence of a residual core of unionized carbon. Artificial diagnostic images are generated from the simulations data to allow direct comparison with experimental x-ray imaging and laser probing diagnostics. The accurate reproduction of the experimental images provides confirmation that the experimentally observed features are a repercussion of the non-linear development-of the m=0 instability in an ionizing medium. (C) 1997 American Institute of Physics.