Separation capability of charged particles by Helmholtz-type direct energy converter with electrodes

The separation capability of charged particles is one of the most important requirements for direct energy converters (DEC) of D–3He fusion reactors. An alternative DEC using Helmholtz coils (Helmholtz DEC) is designed to reduce the self-induced electric field and to separate charged particles when the thermal input is large as 10 MW (8.8 MW/m2). Numerical analyses with a two-dimensional approximation have given the following results. (1) When both electrodes (collectors) are grounded, it can separate ions and electrons with 99.4% ion collection efficiency. (2) When the electric potential is applied to both electrodes as nine cases, the highest separation capability of the charged particles is about 95%. (3) When Cusp DEC, Cusp DEC with closer electrodes and Helmholtz DEC are compared, only Helmholtz DEC can separate the charged particles when the electric potential is applied to the anode.