Fusion applications of rf accelerators

High current RFQ designs have been carried out in the frequency range of 27 to 216 MHz. Particle simulations show that at 27 MHz a D− ion beam of 0.8 A can be accelerated from 0.2 to 1.5 MeV with an efficiency (RF to negative ion beam power) of 73%. Fourteen such RFQ’s can be grouped into a module delivering 9.2 MW of neutral beam power, suitable for non‐inductive current drive in next generation tokamaks. Overall system size is comparable to one based on DC acceleration. At 40 MHz, the system size would be considerably smaller but at the cost of a smaller efficiency of 62%.