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

摘要： 目前直线型中性束注入器中的核心部件强流离子源无法长时间运行在强中子辐射区。面对未来聚变堆的需求，提出了偏转型中性束的概念。利用互相垂直的两线圈的横向磁场改变离子束传输路径方向，使偏转束注入通道在纵向上偏离离子源，从而缓解了离子源区域的辐射问题。通过分析不同形状和角度的磁偏转线圈对束偏转角度和聚散性的影响，确定了满足需求的亥姆霍兹线圈结构。综合平行四边形线圈和梯形线圈磁场分布使束在不同方向上汇聚的优点，优化线圈结构呈现扇形形状，最终实现了束在横向和纵向上的双聚焦设计，以保证负离子束大角度偏转并汇聚注入托卡马克窗口。

关键词: 偏转型中性束, 负离子束, 磁场形状