Optimization of Helical Plasma Confinement

螺旋等离子体约束的优化

• 批准号: 07044108
• 负责人: MATSUOKA Keisuke
• 金额: $ 1.66万
• 依托单位: National Institute for Fusion Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 无数据
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07044108/
• 关键词: helical plasma; Pfirsch-Schluter current; dipole field; quadrupole field; high beta; heavy ion beam probe; 2-D stellarator; ICRF heating

Suppression of Pfirsch-Schluter (P-S) current has been investigated in a conventional helical system as one of helical-plasma-optimization procedures.P-S current causes a deformation of magnetic surfaces which results in the deterioration of the energy confinement.Strong inward shift of magnetic axis shift by a vertical field is effective to suppress the P-S current for an 1=2 stellarator with no shear and for an 1=3 heliotron/torsatron with no rotational transform at axis.For an 1=2 heliotron/torsatron with shear and central rotational transform, it is necessary to elongate the magnetic surface vertically by controlling the quadrupole field in addition to the inward shift by controlling the dipole field.New scenario of stellarator optimization, which was based on the 2-dimensional helical system, was shown.This is more general than the W7-X strategy, but is limited near the magnetic axis.In the 2-D configuration, the particle confinement is dramatically improved compared with a conven … More tional helical system which is of 3-D geometry.This idea helps to promote the quasi-toroidal symmetric stellarator which is now being considered as a new optimized helical system.Heavy ion beam probe is successfully operated in CHS,for the first time in helical machines, to measure the electrostatic potential of the plasma.Here, heavy ion beam trajectory is controlled by octopole deflectors both at the inlet and outlet of the beam.The control method of beam trajectory was compared with that of the russian type and there were some comments from russian side to improve our system.Some of them are for reducing UV light effect which causes emission of secondary electrons resulting in the operation limit on the electron density.Electron heating of ICRF in CHS was compared with L-2 results.In CHS reflection at the high field side R cut-off is newly introduced.ICRF wave physics in real machines is in progress to explain experimental results.Future collaboration on stellarator optimization, transport code in the optimized configuration, diamagnetic measurement, electron distribution function in ECH plasma, modular coil design, has been discussed. Less

作为螺旋等离子体优化程序之一，研究了常规螺旋系统中Pfirsch-Schluter电流的抑制。P-S电流引起磁性表面的变形，导致能量约束的恶化。垂直场对无剪切的1=2仿星器和轴处无旋转变换的1=3日光加速器/扭转子的P-S电流有较强的抑制作用。对于具有剪切和中心旋转变换的1=2日中子/扭转子，除了通过控制偶极子场使磁面向内移动外，还需要通过控制四极子场使磁面纵向拉长。提出了基于二维螺旋系统的仿星器优化方案。这比W7-X策略更通用，但在磁轴附近受到限制。在二维构型下，与传统的三维螺旋结构相比，粒子约束得到了显著改善。这一思想有助于促进拟环面对称仿星器的发展，拟环面对称仿星器目前被认为是一种新的优化螺旋系统。重离子束探针首次在螺旋机中成功地测量了等离子体的静电势。在这里，重离子束的轨迹由光束入口和出口的八爪形偏转器控制。并与俄式的束流轨迹控制方法进行了比较，提出了改进意见。其中一些是为了减少紫外光效应，因为它会导致二次电子的发射，从而导致电子密度的操作限制。并与L-2实验结果进行了比较。在高场侧反射中，新引入了R截止。实际机器中的ICRF波物理学正在进行中，以解释实验结果。讨论了未来在仿星器优化、优化配置中的输运码、抗磁测量、ECH等离子体中的电子分布函数、模块化线圈设计等方面的合作。少

项目成果

V.D.Pustovitov: "Suppression of Pfirsch-Schluter Current by Vertical Magnetic Field in Stellarators" Nuclear Fusion. 36(出版予定). (1996)

V.D.Pustovitov：“仿星器中垂直磁场对 Pfirsch-Schluter 电流的抑制”36（待出版）。

V.D.Pustovitov: "Control of Pfirsch-Schluter Current by External Poloidal Magnetic Field in Conventional Stellarators" Nuclear Fusion (to be submitted).

V.D.Pustovitov：“传统仿星器中外部极向磁场对 Pfirsch-Schluter 电流的控制”核聚变（待提交）。

V.D.Pustovitov: "Control of Pfirsch-Schluter Current by External Poloidal Magnetic Field in Conventional Stellarators" Nuclear Fusion. (投稿中).

V.D.Pustovitov：“传统仿星器中外部极向磁场对 Pfirsch-Schluter 电流的控制”核聚变（正在进行中）。

V.D.Pustovitov: "Suppression of Pfirsch-Schluter Current by Vertical Magnetic Field in Stellarators" Nuclear Fusion. 36. (1996)

V.D.Pustovitov：“仿星器中垂直磁场对 Pfirsch-Schluter 电流的抑制”核聚变。