...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Nuclear fusion >Overview of the Alcator C-Mod program
【24h】

Overview of the Alcator C-Mod program

机译：Alcator C-Mod程序概述

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Research on the Alcator C-Mod tokamak has emphasized RF heating, self-generated flows, momentum transport, scrape-off layer (SOL) turbulence and transport and the physics of transport barrier transitions, stability and control. The machine operates with P_(RF) up to 6 MW corresponding to power densities on the antenna of 10 MW m~(-2). Analysis of rotation profile evolution, produced in the absence of external drive, allows transport of angular momentum in the plasma core to be computed and compared between various operating regimes. Momentum is clearly seen diffusing and convecting from the plasma edge on time scales similar to the energy confinement time and much faster than neo-classical transport. SOL turbulence and transport have been studied with fast scanning electrostatic probes situated at several poloidal locations and with gas puff imaging. Strong poloidal asymmetries are found in profiles and fluctuations, confirming the essential ballooning character of the turbulence and transport. Plasma topology has a dominant effect on the magnitude and direction of both core rotation and SOL flows. The correlation of self-generated plasma flows and topology has led to a novel explanation for the dependence of the H-mode power threshold on the ▽B drift direction. Research into internal transport barriers has focused on control of the barrier strength and location. The foot of the barrier could be moved to larger minor radius by lowering q or B_T. The barriers, which are produced in C-Mod by off-axis RF heating, can be weakened by the application of on-axis power. Gyro-kinetic simulations suggest that the control mechanism is due to the temperature dependence of trapped electron modes which are destabilized by the large density gradients. A set of non-axisymmetric coils was installed allowing intrinsic error fields to be measured and compensated. These also enabled the determination of the mode locking threshold and, by comparison with data from other machines, provided the first direct measurement of size scaling for the threshold. The installation of a new inboard limiter resulted in the reduction of halo currents following disruptions. This effect can be understood in terms of the change in plasma contact with the altered geometry during vertical displacement of the plasma column. Unstable Alfven eigenmodes (AE) were observed in low-density, high-power ICRF heated plasmas. The damping rate of stable AEs was investigated with a pair of active MHD antennae.
机译：对Alcator C-Mod托卡马克的研究强调了RF加热，自生流，动量传输，刮擦层（SOL）湍流和传输以及传输壁垒转换，稳定性和控制的物理原理。该机器以最高6 MW的P_（RF）运行，对应于10 MW m〜（-2）天线上的功率密度。在没有外部驱动的情况下进行的旋转轮廓演变分析可以计算等离子芯中角动量的传输，并在各种运行方式之间进行比较。在与能量限制时间相似的时间尺度上，可以清楚地看到动量从等离子体边缘扩散和对流，并且比新古典运输更快。 SOL的湍流和迁移已经通过位于几个极点位置的快速扫描静电探针和吹气成像进行了研究。在轮廓和波动中发现很强的极向不对称性，证实了湍流和运输的基本膨胀特性。等离子体拓扑结构对堆芯旋转和SOL流动的大小和方向都起主要作用。自生等离子体流与拓扑结构的相关性导致了对H模式功率阈值与▽B漂移方向的依赖关系的新颖解释。内部运输障碍的研究集中在对障碍强度和位置的控制上。通过降低q或B_T，可以将障碍的脚移到较大的较小半径。在C-Mod中通过离轴RF加热产生的势垒可以通过施加轴上功率来减弱。陀螺动力学模拟表明，这种控制机制是由于所捕获的电子模式对温度的依赖性所致，该电子模式因较大的密度梯度而不稳定。安装了一组非轴对称线圈，可以测量和补偿固有误差场。这些还使得能够确定锁模阈值，并且通过与其他机器的数据进行比较，首次对阈值的大小缩放进行了直接测量。安装新的内侧限制器可减少干扰后的光晕电流。可以从等离子柱垂直位移过程中等离子接触与改变的几何形状的变化来理解这种效果。在低密度，高功率ICRF加热的等离子体中观察到不稳定的Alfven本征模式（AE）。用一对有源MHD天线研究了稳定AE的阻尼率。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号