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Generation of Helical SOL Current by on-axisymmetric Divertor Biasing and its effects on SOL Plasma Transport

轴对称偏滤器偏置产生螺旋 SOL 电流及其对 SOL 等离子体输运的影响

基本信息

批准号：
08458133
负责人：
UESUGI Yoshihiko
金额：
$ 0.83万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08458133/
关键词：
divertor biasing non-axisymmetric biasing ExB convective cell heat and particle transport RF induced sheath anttena-plasma coupling anntena heat flux アンテナ熱流局所ダイバータプラズマ SOL・ダイバータバイアスダイバータプラズマダイバータバイアスダイバータ熱負荷コンベクティブセル SOL電流

项目摘要

Heat flux reduction onto the tokamak divertor plate by non-axisymmetric divertor biasing is investigated. ExB convective cells are generated in the scrape off layr (SOL) and divertor plasmas by this non-axisymmetric divertor biasing and SOL and divertor plasma transport is strongly modified. The local divertor biasing experiments have been done in the JFT-2M toka-mak and spatial changes of the plasma potential in the SOL due to local divertor biasing is observed. The spatial structure of the plasma potential during biasing is calculated by 1-DSOL-divertor biasing model and compared with the experimentally observed one. The experimental profile of the plasma potential, which shows the generation of ExB convective cells in the SOL,agrees qualitatively with the theoretical estimation. The particle flux onto the divertor plate is strongly modified by this ExB convective cell formation.In addition to the ExB convective cell formation by DC divertor biasing, Radio Frequency (RF) induced sheath on the RF antenna and its effects on the antenna-plasma coupling are studied in the linear divertor plasma simulator. In the conventional loop antenna large DC negative sheath voltage is induced by RF voltage on the antenna and the antenna heat flux is significantly increased by energetic ion bombardments accelerated by this DC negative sheath. The plasma potential near the antenna is strongly modified by the near RF field and plasma coupling, and the formation of ExB convective cells near the antenna is expected. The study of the RF induced ExB convective cells and their effects on the plasma transport is now in progress.

研究了通过非轴对称偏滤器偏置减少托卡马克偏滤器板上的热通量。通过这种非轴对称偏滤器偏压，在刮掉层 (SOL) 和偏滤器等离子体中产生 ExB 对流单元，并且 SOL 和偏滤器等离子体传输被强烈修改。局部偏滤器偏压实验已在 JFT-2M 托卡马克中进行，并观察到由于局部偏滤器偏压导致的 SOL 中等离子体电势的空间变化。通过1-DSOL-偏滤器偏置模型计算了偏置过程中等离子体电势的空间结构，并与实验观察到的进行了比较。等离子体电势的实验曲线显示了 SOL 中 ExB 对流细胞的产生，与理论估计定性一致。 ExB 对流单元的形成强烈改变了偏滤器板上的粒子通量。除了通过 DC 偏滤器偏置形成 ExB 对流单元之外，还在线性偏滤器等离子体模拟器中研究了 RF 天线上的射频 (RF) 感应护套及其对天线-等离子体耦合的影响。在传统的环形天线中，天线上的射频电压会感应出较大的直流负鞘电压，并且该直流负鞘加速的高能离子轰击会显着增加天线热通量。天线附近的等离子体电势受到近射频场和等离子体耦合的强烈改变，并且预计在天线附近形成 ExB 对流单元。 RF 诱导的 ExB 对流细胞及其对等离子体传输的影响的研究正在进行中。