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Study of Spherical Tokamak of Burning Plasma with TF-CS Hybrid Force-Balanced Coils

TF-CS混合力平衡线圈燃烧等离子体球形托卡马克研究

基本信息

批准号：
17360440
负责人：
TSUTSUI Hiroaki
金额：
$ 10.74万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17360440/
关键词：
spherical torus alpha particle ripple force-balanced coil virial theorem finite larmor radius effect stress internal transport barrier リップル立鳴拡散リップル共鳴拡散磁気エネルギー回生スイッチ拡散係数

项目摘要

Stress distributions of a compact tokamak device Tbdoroki-II with TF-CS hybrid type forte-balanced coils were measured. The measured values were similar to analytically evaluated values, and the reduction of stress was experimentally confirmed.]A fully-inonduced current start up process of a spherical torus (ST) with a transport model of CDBM was numerically simulated. This results show the possibility of a current oscillation by interactions of profiles of internal transport barrier, pressure and boot strap current. A possibility of an over-drive of plasma current was also shown.A finite Larmor radius effect in ST is important because of the weakness of magnetic field compared with that of conventional tokamak. A computation code to calculate trajectory and diffusion coefficient without guiding center approximation was developed. The results were compared with those of conventional tokamak by guiding center approximation. Especially, we investigated an anomalous diffusion by a resonance of toroidal field ripple and banana particles, and evaluated an energy dependence of the diffusion coefficients. The result shows that Larmor motion affects the toroidal phase of banana tip, and softens the resonance. In order to investigate the physical mechanism of the resonance, we use the simple equilibrium configuration with a circular cross section of a conventional tokamak. We numerically found that the peaks of diffusion coefficients appears around the resonance energies of axisymmetric magnetic field. Moreover, distortion of trajectories by the resonance in a phase space makes island configurations, transverse motions by collisions enhance the diffusion.

测量了Tbdoroki-II紧凑型托卡马克装置的Tf-CS混合型强平衡线圈的应力分布。实测值与解析估计值相近，实验证实了应力的降低。]采用CDBM输运模型，对球面环面的全感应电流启动过程进行了数值模拟。这一结果表明，通过内部输运势垒分布、压力和自举电流的相互作用，可能会产生电流振荡。等离子体电流的过驱动也是可能的，有限拉莫尔半径效应在ST中是重要的，因为与常规托卡马克相比，磁场较弱。开发了不需要导引中心近似的弹道和扩散系数计算程序。并与常规托卡马克的导心近似计算结果进行了比较。特别地，我们研究了由环向场波纹和香蕉粒子共振引起的反常扩散，并评估了扩散系数的能量依赖性。结果表明，Larmor运动影响香蕉尖端的环向位相，使其共振变软。为了研究共振的物理机制，我们使用了常规托卡马克的圆形截面的简单平衡组态。数值计算发现，扩散系数的峰值出现在轴对称磁场的共振能量附近。此外，相空间中共振引起的轨迹扭曲使得孤岛构型、碰撞引起的横向运动增强了扩散。