Research of Disruptive Instability based on Anomalous Transport

基于反常输运的破坏性不稳定性研究

• 批准号: 07680545
• 负责人: ITOH Kimitaka
• 金额: $ 1.47万
• 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 Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07680545/
• 关键词: disruptive instability; anomalous transport; strong turbulence; current diffusivity; transition of turbulence; magnetic trigger; pressure gradient; toroidal plasmas; ディスラプティブ不安定性; 異常輸送; 強い乱流; 電流拡散係数; 乱流遷移; 磁気トリガー; 圧力勾配; トロイダルプラズマ; toroidal

The object of this research project is to study the physics mechanisms for the abrupt growth of the plasma deformation (trigger phenomena), which plays the central role in the disruption events, and the rapid evolution of plasma profiles.In this course of research, it is theoretically predicted that there is a turbulence-turbulence transition. It is shown that the abrupt start of growth of the perturbation is possible to occur owing to the transition of turbulence. The sudden change of the growth rate at the onset of the collapse is the direct cause of the collapse events.The details of theoretical finding is as follows. The growth rate of the perturbation is not a smooth function of the plasma parameters, which are driving force of the instabilities. In contrast, the growth rate is subject to a bifurcation when the global driving force reaches a certain threshold value. The evolution of the perturbation turns to be explosive. Plasma deformation that leads to disruption is not a consequence of the linear instabilities, but behaves as a subcritical turbulence. The hysteresis relation between the driving force and the growth rate of perturbations is theoretically predicted.These theoretical view is examined by reviewing experimental observations. By surveying the observations on collapse events, it is found that the abrupt jump of the growth rate is commonly observed for almost all the disruptive phenomena. The new physics picture will be a basis of the future progress of the physics of disruptive phenomena.

本课题的目的是研究等离子体变形（触发现象）突变的物理机制和等离子体轮廓的快速演变。等离子体变形（触发现象）在破坏事件中起着核心作用。在这一研究过程中，理论上预测了湍流-湍流过渡的存在。结果表明，由于湍流的转变，扰动的生长有可能突然开始。崩溃开始时增长率的突然变化是崩溃事件的直接原因。具体的理论发现如下。扰动的增长速度不是等离子体参数的平滑函数，而等离子体参数是不稳定性的驱动力。相反，当全球驱动力达到一定阈值时，增长率就会出现分岔。扰动的演化变成爆炸性的。导致破坏的等离子体变形不是线性不稳定性的结果，而是表现为亚临界湍流。从理论上预测了驱动力与扰动增长率之间的滞后关系。这些理论观点是通过回顾实验观察来检验的。通过对崩塌事件的观测，发现几乎所有的破坏现象都普遍存在增长率的突变。新的物理图景将成为研究破坏性现象的物理学未来进展的基础。

项目成果

S.-I.ITOH, et al.: "Edge Localized Modes as New Bifurcation in Tokamaks" Phys.Rev.Lett.76. 920-923 (1996)

S.-I.ITOH 等人：“边缘局域化模式作为托卡马克中的新分叉”Phys.Rev.Lett.76。

K.ITOH, et al.: "Current diffusive interchange mode turbulence at low magnetic shear" Plasma Phys.Contr.Fusion. 39. 1561-1570 (1997)

K.ITOH 等人：“低磁剪切下的当前扩散交换模式湍流”Plasma Phys.Contr.Fusion。

A.Fujisawa, ...., K.ITOH, et al.: "Direct observation of potential profiles with a 200KeV heavy ion beam probe on the Compact Helical Systems" Phys.Plasmas. 4. 1357-1361 (1997)

A.Fujisawa, ...., K.ITOH 等人：“在紧凑螺旋系统上使用 200KeV 重离子束探针直接观察电势分布”Phys.Plasmas。

A.Fujisawa, ..., K.ITOH, et al.: "Dynamic Behavior of potential in the plasma core of the CHS Heliotron/torsatron" Phys.Rev.Lett.79. 1054-1057 (1997)

A.Fujisawa, ..., K.ITOH 等人：“CHS Heliotron/torsatron 等离子体核心电势的动态行为”Phys.Rev.Lett.79。

Tateishi, S.-I.ITOH, et al.: "The effect of He-ash poisoning on L-mode and high βp-mode operations in ITER-like plasmas" Plasma Phys.Contr.Fusion. 39. 1871-1885 (1997)

Tateishi, S.-I.ITOH 等人：“He-ash 中毒对类 ITER 等离子体中 L 模式和高 βp 模式操作的影响”Plasma Phys.Contr.Fusion 39. 1871-1885（ 1997）