Optimization of the inner array in a nested array Z-pinch

Summary form only given. Nested wire arrays have been used to improve pinch quality and X-ray power. Numerical simulations suggest that the inner array acts to reduce the growth of the MHD Rayleigh-Taylor (RT) instability present in the outer array prior to impact. This instability develops during the implosion phase and can significantly broaden the pinch at stagnation unless mitigated. Using a standard 40 mm diameter single array, a numerical parameter study was performed to investigate the optimal mass and location of the additional inner array which would best mitigate the RT instability. The implosion performance was characterized by the peak radial plasma kinetic energy. Initially, a 1-D slug model was used to determine the optimal configuration. This model suggested minimal loss in peak kinetic energy if the inner shell was located between 16 and 22 mm. This information was then used to model the instability effects with a 2-D MHD code, MACH2.