Problems and prospects for microsecond pulsed power above ten megamperes

Systems, such as Shiva Star, Atlas, and magnetic-flux compression generators (MCGs), that can deliver several megajoules at currents above 10 MA offer the opportunity for many interesting experiments in controlled fusion technology and basic material dynamics. Typical current rise-times of a few microseconds result, even with low inductance (<20 nH) circuitry, because several megajoules are delivered at less than 200 kV. This means that conductor surfaces can move significantly relative to the skin-layer thickness, and surface plasmas can interfere with power flow. Success with such multimegampere technology, therefore, requires considerable attention to the detailed design of joints and conductor surfaces. This paper discusses these and other design considerations. It also describes opportunities enabled by operation above 10 MA.