Progress in Heavy Ion Fusion Research*

The Heavy Ion Fusion program has recently transitioned from small scaled experiments to experiments with driver-scale currents at low energy. Two new experiments are in operation, the High Current Experiment (HCX), and the Neutralized Transport Experiment (NTX). The space charge in these experiments is similar to that of a driver, and enables investigation of the interaction of the beam with electrons, both those produced by beam halo scraping surfaces, and also electrons intentionally introduced to assist a neutralized focus. Other HIF-VNL experiments are being used to investigate a new approach to beam injectors. At the University of Maryland, an electron ring is being used to explore transport issues of interest. The design of all of these experiments, their goals, and recent experimental results and computer simulation, will be described. Future programmatic plans for Heavy Ion Fusion will also be discussed, including the scientific objectives and physics design of a proposed new next-step proof-of-principle experiment for Heavy Ion Fusion, the Integrated Beam Experiment (IBX). This experiment would constitute an integrated source-to-target test of beam dynamics using a driver-scale beam. Many beam manipulations, such as drift compression (integrated with final focus and subsequent neutralization), long-length-scale transport, longitudinal wave dynamics, and bending of space-charge-dominated beams would be tested at scale for the first time in this experiment. Finally, the programmatic importance, parameters, and scientific mission of a proof-of-performance experiment, the Integrated Research Experiment, will be discussed.