Cesium Effects on Enhancing Negative Ion Production in and Negative Ion Extraction from the Hybrid Type Negative Ion Sources

铯对增强混合型负离子源负离子产生和负离子提取的作用

基本信息

批准号：
06452424
负责人：
FUKUMASA Osamu
金额：
$ 4.1万
依托单位：
Yamaguchi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

High Current H^-/D^- ion sources are required for the preparation of neutral beams in the fusion community, i.e.Neutral Beam Injection (NBI) heating of fusion plasmas. To this end, basic processes for enhancementof H^-/D^- production in and extraction from the hybrid type negative ion sources, have been studied, experimentally, theoreticelly and computationally (i.e.particle simulation). Findings are as follows :1.It is confirmed that D^- ions are produced by the so-called two step process as for H^- production. Namely, D^- ions are generated by dissociative attachment of slow plasma electrons to highly vibrationally excited molecules, and these molecules are produced by collisional excitation of fast electrons.2.With the use of double plasma method (namely, the energy distribution of fast electrons are well controlled), enhancement of H^-/D^- production caused by increasing fast electrons is clearly observed.3.With the change of discharge conditions, D^- ions are apparently higher than H^- ions under some plasma parameters.4.According to the numerical simulation of the negative ion model, for both cases with and without cesium effects, plasma parameter dependences of H^-/D^- production are well reproduced.5.With the use of the electrostatic particle simulation code (two-dimensional in space and three-dimensional in velocity space), electron transport and the potential formation across the magnetic filter, and the extraction of negative ions from the source are studied. It is found that the collisionless anomalous diffusion of electrons plays an important role in the determining the potential structure where the potential of the main plasma is higher than that of the diffused plasma.

高电流H^ - /d^ - 离子源是在融合群落中制备中性束需要的，即融合等离子体的中性束注射（NBI）加热。为此，已经在实验上，理论上和计算（即粒子模拟）研究了H^ - /d^ - 产生和从混合型负离子源中提取的基本过程。结果如下：1。证实D^ - 离子是由所谓的两个步骤过程所产生的，即H^ - 生产。就是说，通过缓慢的血浆电子与高度振动激发的分子的解离性附着性产生d^ - 离子，这些分子是通过快速电子的碰撞激发而产生的。2。使用双等离子体方法的使用（即，快速电子的能量分布均可增强h^ - /d^ - /dy^fast fast fast-d^ - /d^fast fast-d^ - /d^fast fast fast-d^ - /d^fast fast-d^ - /d^ - d^ - /dementy fasterty的生产。在某些血浆参数下，d^ - 离子的条件显然高于H^ - 离子。4。符合负离子模型的数值模拟，对于具有和没有纤维效应的情况下的两个情况，H^ - /d^ - 产生的等离子体参数依赖性良好。研究了整个磁过滤器的电势形成，并研究了从源中提取负离子。发现电子的无碰撞异常扩散在确定主要等离子体电位高于扩散等离子体的电势时起着重要作用。