Parameter optimization of quasi-spherical wire-arrays based on multi-element model

Based on the multi-element thin-shell model, the parameters of the quasi-spherical wire-arrays are optimized to obtain the final plasma shells with anticipated implosion characters. By optimizing the initial wire-array geometry, we can implode the wire array to the final plasma shell with a suitable aspect ratio, and the aspect ratio is not sensitive to the initial load mass. For a given current shape with a peak current of 1.2 MA and a risetime of 80 ns, the linear density of the wire array with an initial length of 15.4 mm is optimized to maximize the final kinetic energy. Numerical results indicate that the final plasma shell with an equatorial radius of 2 mm and an aspect ratio of 1 obtains maximum kinetic energy 1.5 kJ when the initial linear density takes 150 g/cm. Optimization of the initial linear density is carried out for the current waveforms with different peak values and different risetimes, and the results indicate that the optimized maximum kinetic energy is proportional to the square of the current peak value and the corresponding linear mass is proportional to the square of the current risetime.