MHD Database for Design of Quasi-axisymmetric Stellarator

准轴对称仿星器设计的 MHD 数据库

• 批准号: 12480128
• 负责人: MATSUOKA Keisuke
• 金额: $ 2.88万
• 依托单位: Natiomal Institute for Fusion Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12480128/
• 关键词: quasi-axisymmetric stellarator; CHS-qa; Mercier criterion; extemal kink instability; hootstrap current; tearing mode; ballooning mode; CHS; 準軸対称ヘリカル磁場配置; ブートストラップ電流; ヘリカル型プラズマ; 準軸対称性; ベータ値; 理想MHDモード; 抵抗性壁モード

MHD stability of quasi-axisymmetric stellarator CHS-qa is estimated by referring to CHS experimental data and by using computer codes. Although magnetic configurations of CHS-qa and CHS (low aspect ratio heliotron / torsatron) are different, stability criteria should be available for both configurations. Mercier criterion on the local interchange mode has been widely used as a guideline for evaluating MHD stability of CHS and LHD, because both machines are of a magnetic hill even in the finite J3 configuration, which makes the configurations possibly unstable against ideal interchange modes. Experimental results of CHS showed that finite <β> plasmas, where instabilities are expected from Mercier criterion, did not show any deleterious effect on the stored energy. Recent CHS experiments again confirmed this result for more strongly inward shift of vacuum magnetic axis than before, where the magnetic hill becomes stronger. This was also confirmed recently in LHD experiments. The important conclusion is that it is not necessary to take serious account of Mercier criterion in evaluating MHD stability of CHS-qa. In CHS-qa plasmas with finite <β>, the bootstrap current flows in the direction to augment the vacuum rotational transform. The current might excite tearing modes and external kink modes, where m=2/n=l mode is the most dangerous one. By inducing Ohmic and beam driven currents in CHS, MHD modes with m=2/n=l have been studied. Again there is no deleterious effect on the plasma performance. Because the resonant surface of m=2/n=l can not exist in vacuum in CHS, the external kink mode can not be simulated in the experiment. The mode has been analyzed by using Terpsichore and CAS3D codes in CHS-qa. The plasma is stable up to <β> of 2.5 - 3%. The ballooning mode has been analyzed with Terpsichore WBAL and Cobra codes, giving stability <β> of up to about 3%.

利用CHS实验数据和计算机程序对准轴对称仿星器CHS-qa的MHD稳定性进行了估计。虽然CHS-qa和CHS（低纵横比日光/扭转加速器）的磁配置是不同的，稳定性标准应可用于这两种配置。局部交换模的Mercier判据已被广泛地用作评价CHS和LHD的MHD稳定性的准则，因为即使在有限的J3位形中，这两种机器也是磁丘，这使得位形可能对理想交换模不稳定。CHS的实验结果表明，有限<β>等离子体，其中的不稳定性预计从Mercier标准，并没有表现出任何有害的影响存储的能量。最近的CHS实验再次证实了这一结果，因为真空磁轴比以前更强烈地向内移动，磁丘变得更强。这一点在最近的LHD实验中也得到了证实。重要的结论是，在评估CHS-qa的MHD稳定性时，没有必要认真考虑Mercier准则。在具有有限<β>的CHS-qa等离子体中，自举电流的方向是增强真空转动变换的方向。电流可能激发撕裂模和外扭结模，其中m=2/n= 1模是最危险的模。通过在CHS中引入欧姆电流和束流驱动电流，研究了m=2/n= 1的MHD模。同样，对等离子体性能没有有害影响。由于CHS在真空中不可能存在m=2/n= 1的谐振面，实验中无法模拟出外扭结模。在CHS-qa中使用Terpsichore和CAS 3D程序对该模式进行了分析。血浆在高达2.5 - 3%的<β>下是稳定的。用Terpsichore WBAL和Cobra代码分析了气球模式，给出了高达约3%的稳定性<β>。

项目成果

S.Okamura, K.Matsuoka, S.Nishimura et al.: "Physics and engineering design of the low aspect-ratio quasi-axisymmetric stellarator CHS-qa"Nuclear Fusion. 41・12. 1865-1871 (2001)

S.Okamura、K.Matsuoka、S.Nishimura 等：“低纵横比准轴对称仿星器 CHS-qa 的物理和工程设计”核聚变 41・12 (2001)。

K.Matsuoka, S.Okamura, S.Nishimura et al.: "Quasi-axisymmetric Stellarator CHS-qa"Journal of Plasma and Fusion Research. 4. 111-116 (2001)

K.Matsuoka、S.Okamura、S.Nishimura 等人：“准轴对称仿星器 CHS-qa”等离子体与聚变研究杂志。

S. Okamura, K. Matsuoka, S. Nishimura et al: "esign of Quasi-axisymmetric Stellarator CHS-qa (in Japanese)"Journal of Plasma and Fusion Research. Vol.78. 166 (2002)

S. Okamura、K. Matsuoka、S. Nishimura 等人：“拟轴对称仿星器 CHS-qa 的设计（日文）”等离子与聚变研究杂志。

K. Matsuoka, S. Okamura, S. Nishimura et aL: "Quasi-axisymmetric Stellarator CHS-qa"Journal of Plasma and Fusion Research SERIES. Vol.4. 111 (2001)

K. Matsuoka、S. Okamura、S. Nishimura 等人：“准轴对称仿星器 CHS-qa”等离子体与聚变研究杂志系列。

S. Okamura, K. Matsuoka, S. Nishimura, et al.: "Physics and engineering design of the low aspect-ratio quasi-axisymmetric stellarator CHS-qa"Nuclear Fusion. Vol.41. 1865 (2001)

S. Okamura、K. Matsuoka、S. Nishimura 等人：“低纵横比准轴对称仿星器 CHS-qa 的物理和工程设计”核聚变。