Update on Progress and Current Research in the Development of Heavy Ion Fusion

Since the completion of the Robust Point Design (RPD) for a heavy ion fusion power plant, progress has been made in addressing key issues and some possible new directions have emerged. Work has continued on thick liquid wall chambers, which are particularly well suited to heavy ion fusion since they allow compact chambers minimizing the standoff for the final focus magnets and thus improving beam focusing on target. Work has continued on HIF indirect-drive targets in an attempt to allow larger spot sizes than the ~2 mm spots required by the baseline target in the RPD. A promising approach is the use of shine shields at both ends of the hohlraum, which allows beams to fill the entire 5-mm-radius target. This larger spot size target design opens the door to other driver and focusing schemes. Work has started exploring a modular driver approach in which many individual accelerators provide the total beam energy on target as opposed to the single accelerator with many (~100) individual beamlets threading common induction cores. Neutralized drift compression and plasma channel focusing are being studied as a way to deliver these high current beams to target. We have also started investigating new chamber designs that would be compatible with this focusing scheme, in particular designs using a vortex flow configuration to establish the thick liquid wall. This paper highlights progress since the last Technology of Fusion Energy (TOFE) Conference.