Multimegajoule Electromagnetic Implosion of Shaped Solid-Density Liners

Electromagnetic implosions of shaped cylindrical aluminum liners that remain at solid density are discussed. The approximate liner parameters have an initial radius of 3 to 4 cm, are 4 cm in height, and are ∼0.1 cm thick. The liners are driven by the Shiva Star 1300-µf capacitor bank at an 84-kV charging voltage and an ∼30-nH total initial inductance (including implosion load). The discharge current travels along the length of the liner and rises to 14 MA in ∼8 µs. The implosion time is ∼12 µs. Diagnostics include inductive current and capacitive voltage probes, magnetic probes, and radiography. Both right-circular cylinder and conical liner implosion data are displayed and discussed. Radiography indicates implosion behavior substantially consistent with two-dimensional magnetohydrodynamic calculations, which predict inner surface implosion velocities exceeding 20 km/s, and compressed density of two to three times solid density. Less growth of perturbations is evident for the conical liner (∼1% thickness tolerance) than for the right-circular cylindrical liner (∼3% thickness tolerance).