TRANSPORT EFFICIENCY STUDIES FOR LIGHT-ION INERTIAL CONFINEMENT FUSION SYSTEMS USING BALLISTIC TRANSPORT WITH SOLENOIDAL LENS FOCUSING

The proposed Laboratory Microfusion Facility (LMF) will require greate r than or equal to 10 MJ of 30 MeV lithium ions to be transported and focused onto high-gain, high-yield inertial confinement fusion targets ,.The light-ion LMF approach uses a multimodular system with individua l ion extraction diodes as beam sources, Previous work examined the ef fect of time-of-flight bunching on energy transport efficiency, eta(t) , under realistic constraints on diode operation, beam transport, and packing. Target design considerations suggest that the instantaneous p ower efficiency, Gamma(t), be maximized near peak power, Because of ti me-of-flight bunching, peak power occurs at the end of the power pulse for LMF designs, This work examines the effect of power efficiency tu ning on eta(t) for an LMF design using ballistic transport with soleno idal lens focusing, Results indicate that tuning the power pulse to ma ximize Gamma(t) at about three-quarters through the pulse provides hig h power efficiency at the end of the pulse while still maintaining hig h eta(t). In addition to power efficiency tuning, effects on eta(t) fr om variations of the diode impedance model and the diode voltage wavef orm are also examined.