Research on Disruption and Thermal Quench of Long-Pulse Discharge

长脉冲放电的破坏与热猝灭研究

• 批准号: 05680398
• 负责人: NAKAMURA Kazuo
• 金额: $ 1.02万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05680398/
• 关键词: Long-pulse discharge; Disruption; Thermal quench; Current disruption; Lower hybrid current drive; 長時間放置; デイスラプション

(1) Controllable plasma current density distribution is obtainable by numerical calculation of ray-trace and Fokker-Planck equations. We developed the numerical calculation program and applied it to the 8.2 GHz LHCD plasma. Although the absolute driven current depends on the model of energy gap, the dependence of the driven plasma current profile on the line-averaged electron density coincides the dependence of the profile estimated from the measured hard X-ray profile emitted from high-energy electrons.(2) We measured the impurity density distribution of 8.2 GHz LHCD discharge with multi-channel vacuum ultra violet spectrometer. Molybdenum impurity, which is the material of the poloidal limiter, increases temporally, and results in discharge termination. This phenomenon suggests the thermal quench due to impurity emission cooling and following current disruption.(3) To avoid the impurity increase in the plasma, we made a single-null divertor configuration in the superconducting tokamak TRIAM-1M.Assuming the thermal load profile onto te divertor plate, we calculated 2-dimentional temperature distribution in the divertor plate and the stainless steel supporting plate. By comparing the result with the temperature of the water-cooled stainless steel plate measured by CA thermo-couple, the total thermal load onto the divertor plate was estimated to be 20-35 % of the RF input power.(4) What current profile does a plasma realize in steady state? This problem coincides the problem what confinement is realized in steady state. We studied theoretically on the effect of the current profile on the transport coefficient. And we formulated an element of "profile control research" from the view point of "plasma confinement". According to the formulation, we studied theoretically on the confinement improvement phenomena concerning LHCD and high-beta oriented experiments.

(1)通过射线追踪和福克-普朗克方程的数值计算，得到了可控的等离子体电流密度分布。我们开发了数值计算程序，并将其应用于8.2 GHz的LHCD等离子体。虽然绝对驱动电流依赖于能隙模型，但驱动等离子体电流分布对线平均电子密度的依赖性与从高能电子发射的测量硬X射线分布估计的分布的依赖性一致。(2)用多道真空紫外光谱仪测量了8.2GHz LHCD放电的杂质浓度分布。作为极向限制器材料的钼杂质随时间增加，并导致放电终止。这种现象表明，由于杂质排放冷却和随后的电流中断的热淬火。(3)为了避免等离子体中杂质的增加，在超导托卡马克TRIAM-1 M装置上采用单零偏滤器结构，假设偏滤器板上的热负荷分布，计算了偏滤器板和不锈钢支撑板的二维温度分布。通过与CA热电偶测量的水冷不锈钢板的温度的比较，偏滤器板上的总热负荷估计为RF输入功率的20- 35%。(4)等离子体在稳定状态下实现什么样的电流分布？这个问题与定常状态下如何实现约束的问题是一致的。从理论上研究了电流分布对输运系数的影响。并从“等离子体约束”的角度阐述了“调剖研究”的内容。根据该公式，我们从理论上研究了LHCD和高β取向实验中的约束改善现象。

项目成果

伊藤 早苗: "On Scaling Laws in Scrape-off-layer Plasmas" Plasma Phys.Control.Fusion. 36. 1845-1851 (1994)

伊藤早苗：“论刮离层等离子体的缩放定律” Plasma Phys.Control.Fusion 36。1845-1851 (1994)

K.Itoh, et al.: "Cross Field Ion Motion at Sawtooth Crash" J.Phys.Soc.Jpn.62. 399-402 (1993)

K.Itoh 等人：“锯齿碰撞时的跨场离子运动”J.Phys.Soc.Jpn.62。

K.Itoh, et al.: "Beta-Limiting Phenomena due to Global Resistive Interchange Mode in High-Aspect-Ratio Torsatron/Heliotron" Plasma Phys.Contr.Fusion. 35. 723-732 (1993)

K.Itoh 等人：“高纵横比 Torsatron/Heliotron 中全局电阻交换模式导致的 Beta 限制现象”等离子 Phys.Contr.Fusion。

M.Yagi, et al.: "Analysis of the Current-Diffusive Ballooning Mode" Phys.Fluids B. 5. 3702-3711 (1993)

M.Yagi 等人：“电流扩散气球模式的分析”Phys.Fluids B. 5. 3702-3711 (1993)

K.Itoh: "Self-sustained Turbulence and L-mode Confinement in Toroidal Plaamas II" Plasma Phys.Control.Fusion. 36. 1501-1520 (1994)

K.Itoh：“环形等离子体 II 中的自持湍流和 L 模式限制”等离子体物理控制融合。