Recent experimental results at the Sandia National Laboratory (e.g., S
anford et al. [1]) have shown that the Xray power increases as the num
ber of wires n employed is increased, with a sharper increase in power
when the wire gap is below a critical value. This paper proposes a mo
del that can not only explain these phenomena, but also shows how the
initial perturbations that lead to the Rayleigh-Taylor instability sca
le as n(-1/2). The model predicts the shell thickness at merger of the
expanding separate wires which will mainly determine the final pinch
radius. The largest amplitude Rayleigh-Taylor mode at the pinch time i
s also found, in reasonable agreement with experiment.