关键词: 偏转型中性束, 负离子束, 磁场形状

Abstract: The core component of the current linear neutral beam injector, i.e. the strong current ion source,cannot operate in the strong neutron radiation region for a long time. Facing the demand of the future fusion reactor, the concept of the deflecting neutral beam is proposed. Using the transverse magnetic field of the two coils perpendicular to each other to change the direction of the ion beam transmission path, the beam injection channel is deflected away from the ion source in the longitudinal direction, so that the radiation problem in the ion source region is alleviated. By analyzing the effects of different shapes and angles of magnetic deflection coils on the beam deflection angle and convergence, the Helmholtz coil structure to meet the demand is determined, and the advantages of parallelogram coil and trapezoidal coil magnetic field distribution to make the beam converge in different directions are integrated to optimize the coil structure to present a fan shape, which finally realizes the dual-focusing design of the beam in the transverse and longitudinal directions to ensure the negative ion beam deflection at a large angle and convergence for injection into the tokamak windows.

Key words: Deflected neutral beam, Negative ion beam, Magnetic field shape