多峰离子源的三维数值模拟优化与设计

3D simulation optimization and design of multicusp ion source

本文理论计算了多峰离子源永磁体,采用二体碰撞模型处理电子之间的库仑碰撞,运用空碰撞方法处理电子与氢元素相关粒子碰撞,开发了全三维粒子模拟-蒙特卡罗模拟算法,并采用此软件对热门多峰离子源JET-60U的两种优化设计模型进行数值模拟研究,探索了两种离子源空间分布特性和体积负氢离子产率相关问题,提出了负氢离子源设计的基本思想:适当调整离子源多峰磁场分布情况可以输出均匀离子束;适当调整引出磁场大小和离子源结构,可以达到离子束空间均匀性和高产率兼顾的效果.

In this paper, a permanent magnet of multicusp ion source is calculated in theory, using the ＂binary collision＂ model to deal with coulomb collision between electrons. Collision between electrons and hydrogen species is treated with the ＂null-collision＂ model. Therefore, the three-dimensional PIC-MCC simulation algorithm is developed. Two optimization design models of multicusp ion source, ET-60U, are simulated by the software. Also, the spatial distribution characteristics and the relevant issues of the volume negative hydrogen ion production rate of the two kinds of ion sources are explored. Finally, The basic idea about the design of the negative hydrogen ion source is proposed, indicating that appropriately regulating the magnetic field distribution of the multicusp ion source can produce uniform ion beam, and that appropriately adjusting the size of the extraction magnetic field and the ion source structure can obtain both the ion beam spatial uniformity and the high production rate.