Numerical analysis of primary electrons in a tandem-type negative ion source
Numerical analysis of primary electrons in a tandem-type negative ion source
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DOI：
10.1063/1.2171755
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发表时间：
2006-03
影响因子：
1.6
通讯作者：
K. Katoh;N. Takado;A. Hatayama;M. Hanada;T. Seki;T. Inoue
中科院分区：
文献类型：
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作者：
K. Katoh;N. Takado;A. Hatayama;M. Hanada;T. Seki;T. Inoue
为了阐明串联型负离子源中观察到的等离子体空间不均匀的物理机制，用三维蒙特卡罗模拟程序分析了初级电子输运过程。在该模型中，电子的运动方程得到了数值求解。考虑了真实的几何形状和磁场配置。模型中还包括了与中性粒子的各种碰撞过程。模拟结果表明：(1)由于滤光器磁区的磁漂移，从源区到引出区的初级电子已经丢失；(2)磁漂移速度在侧壁附近具有相反的方向。磁漂移的影响是解释实验中观察到的空间不均匀的可能原因之一。
To clarify the physical mechanism of the plasma spatial nonuniformity observed in tandem-type negative-ion sources, the primary electron-transport process has been analyzed by a three-dimensional Monte Carlo simulation code. In the model, equations of motion for electrons are numerically solved. The realistic geometry and magnetic-field configuration are taken into account. Various collision processes with neutral particles are also included in the model. The simulation results show that (1) the primary electrons have been lost from the source region to the extraction region due to the magnetic drift in the filter magnetic region and (2) the magnetic drift velocities have opposite directions near the sidewalls. The effect of the magnetic drift is one of the possible causes to explain the spatial nonuniformity observed in the experiment.