Heavy ion beams for Inertial Fusion Energy

In heavy ion fusion, fuel compression, heating and ignition is achieved with beams of heavy ions, complementary to laser driven IFE. Heavy ion drivers are attractive because of high accelerator wall-plug efficiency (>20%), robustness of accelerator optics, and ion energy deposition in fusion targets without plasma instabilities. Over the last decade, HIF driver R&D has progressed, but at a much slower rate compared to lasers and pulsed power approaches. We describe opportunities to advance HIF driver science and technology to reach the driver capabilities of a viable fusion power. A new class of heavy ion beams currently being developed at FAIR/GSI will (soon) enable experiments with multi-kJ GeV heavy ion pulses. This will advance our understanding of beam control and target coupling, together with advanced simulations. In paralle, recent advancements in particle accelerator R&D can be leveraged to inform a path to a compelling blueprint for HIF drivers. These include progress in lower cost pulsed power for induction linacs, massively scaled multi-beam RF linacs made by additive manufacturing, a new generation of high field superconducting magnets, new designs for recirculating linacs, and advances in laser-plasma ion acceleration.