Transport and focusing considerations for light ion ICF systems

The Laboratory Microfusion Facility (LMF) has been proposed for the study of high-gain, high-yield ICF targets. A number of transport and focusing schemes are being considered for LMF. The schemes which have been studied most extensively include ballistic transport with solenoidal lens focusing, z-discharge channel transport and wire-guided transport. Transport efficiency η_t has been calculated as a function of various system parameters so that point designs can be developed for each scheme. The analysis takes into account target requirements and realistic constraints on diode source brightness, packing, and beam transport. The effect on η_t. of voltage ramping for time-of-flight bunching has also been considered. Results show that transport efficiencies of >; 50% can be obtained for all three systems with diode-microdivergence (5-10 mrad), diode-radius (10-15 cm), and diode-ion-current-density (2-10 kA/cm²) values which seem achievable.