Beta limits in long-pulse tokamak discharges
Beta limits in long-pulse tokamak discharges
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DOI：
10.1063/1.872270
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发表时间：
1997-05-01
影响因子：
2.2
通讯作者：
Yoshino, R
中科院分区：
文献类型：
--
作者：
Sauter, O;LaHaye, RJ;Yoshino, R
长脉冲托卡马克放电在低碰撞性下实现的最大归一化β明显福尔斯短脉冲放电中观察到的和理想MHD理论预测的。最近的长脉冲实验，特别是模拟国际热核聚变实验堆（ITER）的实验[M。Rosenbluth等人，Plasma Physics and Controlled Nuclear Fusion（International Atomic Energy Agency，维也纳，1995），Vol.2，p.517]具有低碰撞性nu（e）* 的方案通常受到低m/n非理想磁流体动力学（MHD）模式的限制。饱和MHD模式的影响是限制时间减少10%-20%，这取决于岛的大小和位置，并可能导致中断。撕裂模式的新古典不稳定，包括扰动螺旋自举电流的影响，最近的理论是成功的解释的电阻模式的定性行为和最近的结果是一致的饱和岛的大小。此外，一个很强的相关性之间的发病观察到这些低m/n模式与锯齿，边缘本地化模式（ELM），或鱼骨事件。与理论所要求的种子岛一致。我们将集中在传统的电阻和新古典理论之间的定量比较，几台机器的实验结果，都观察到这些低最小值的非理想模式。这使我们能够挑出的关键问题，在预测的ITER大小的托卡马克的长脉冲β限制，并讨论可能的等离子体控制方法，可以增加软β限制，减少种子扰动，和/或减少约束的影响。(C)1997年美国物理学会。
The maximum normalized beta achieved in long-pulse tokamak discharges at low collisionality falls significantly below both that observed in short pulse discharges and that predicted by the ideal MHD theory. Recent long-pulse experiments, in particular those simulating the International Thermonuclear Experimental Reactor (ITER) [M. Rosenbluth et al., Plasma Physics and Controlled Nuclear Fusion (International Atomic Energy Agency, Vienna, 1995), Vol. 2, p. 517] scenarios with low collisionality nu(e)*, are often limited by low-m/n nonideal magnetohydrodynamic (MHD) modes. The effect of saturated MHD modes is a reduction of the confinement time by 10%-20%, depending on the island size and location, and can lead to a disruption. Recent theories on neoclassical destabilization of tearing modes, including the effects of a perturbed helical bootstrap current, are successful in explaining the qualitative behavior of the resistive modes and recent results are consistent with the size of the saturated islands. Also, a strong correlation is observed between the onset of these low-m/n modes with sawteeth, edge localized modes (ELM), or fishbone events. consistent with the seed island required by the theory. We will focus on a quantitative comparison between both the conventional resistive and neoclassical theories, and the experimental results of several machines, which have all observed these low-min nonideal modes. This enables us to single out the key issues in projecting the long-pulse beta limits of ITER-size tokamaks and also to discuss possible plasma control methods that can increase the soft beta limit, decrease the seed perturbations, and/or diminish the effects on confinement. (C) 1997 American Institute of Physics.