Quantification of the impact of large and small-scale instabilities on the fast-ion confinement in ASDEX Upgrade
Quantification of the impact of large and small-scale instabilities on the fast-ion confinement in ASDEX Upgrade
复制标题
量化 ASDEX Upgrade 中大尺度和小尺度不稳定性对快离子限制的影响
DOI：
10.1088/0741-3335/57/1/014018
复制
发表时间：
2014
影响因子：
2.2
通讯作者：
M. Willensdorfer
中科院分区：
文献类型：
--
作者：
B. Geiger;M. Weiland;A. Mlynek;M. Reich;A. Bock;M. Dunne;R. Dux;E. Fable;R. Fischer;M. Garcia;J. Hobirk;C. Hopf;S. Nielsen;Tomáš Odstrčil;C. Rapson;D. Rittich;F. Ryter;M. Salewski;P. Schneider;G. Tardini;M. Willensdorfer
在ASDEX升级托卡马克上，研究了由中性束注入(NBI)产生的禁闭快离子。在表现出强烈锯齿碰撞的等离子体中，观察到了锯齿引起的主要通过快离子的内部重分布，这与基于Kadomtsev模型的理论预测非常一致。在锯齿形碰撞之间，鱼骨模被激发，然而，这并不会导致全球快离子数量的可测量变化。在没有强磁流体力学(MHD)模式的轴上和离轴NBI实验中，快离子测量结果与新经典理论的预测非常吻合。这表明在这些条件下，MHD诱导的(大尺度)以及可能的湍流诱导的(小尺度)快离子输运可以忽略不计。然而，在研究加热功率高达10 mW的离轴NBI电流驱动效率的放电中，快离子测量结果与假设弱能级反常快离子输运的理论预测最吻合。这也与内部电感的测量、运动斯塔克效应诊断和一种新的偏振诊断相一致：当改变NBI注入几何形状时，快离子驱动的电流分布明显被修改，并且测量结果与假设微弱反常快离子扩散的预测最吻合。
The confinement fast ions, generated by neutral beam injection (NBI), has been investigated at the ASDEX Upgrade tokamak. In plasmas that exhibit strong sawtooth crashes, a significant sawtooth-induced internal redistribution of mainly passing fast ions is observed, which is in very good agreement with the theoretical predictions based on the Kadomtsev model. Between the sawtooth crashes, the fishbone modes are excited which, however, do not cause measurable changes in the global fast-ion population. During experiments with on- and off-axis NBI and without strong magnetohydrodynamic (MHD) modes, the fast-ion measurements agree very well with the neo-classical predictions. This shows that the MHD-induced (large-scale), as well as a possible turbulence-induced (small-scale) fast-ion transport is negligible under these conditions. However, in discharges performed to study the off-axis NBI current drive efficiency with up to 10 MW of heating power, the fast-ion measurements agree best with the theoretical predictions that assume a weak level anomalous fast-ion transport. This is also in agreement with measurements of the internal inductance, a Motional Stark Effect diagnostic and a novel polarimetry diagnostic: the fast-ion driven current profile is clearly modified when changing the NBI injection geometry and the measurements agree best with the predictions that assume weak anomalous fast-ion diffusion.
影响因子：
3.3
作者：
Shimada, M.;Campbell, D. J.;Sipps, A. C. C.
通讯作者：
Sipps, A. C. C.