Low to high confinement transition theory of finite-beta drift-wave driven shear flow and its comparison with data from DIII-D
Low to high confinement transition theory of finite-beta drift-wave driven shear flow and its comparison with data from DIII-D
复制标题
有限β漂移波驱动剪切流低到高约束转变理论及其与DIII-D数据的比较
DOI：
10.1063/1.1638381
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发表时间：
2004
影响因子：
2.2
通讯作者：
P. Gohil
中科院分区：
文献类型：
--
作者：
P. Guzdar;R. G. Kleva;R. Groebner;P. Gohil
托卡马克中边缘湍流的剪切流稳定化已经成为在高(H)限制模等离子体中观察到的限制改善的公认范例。给出了有限β等离子体中纬向流和场的产生结果。这个理论给出了一个从低到高(L-H)限制模分叉的判据，它与Te/Ln成正比，其中Te是电子温度，Ln是密度梯度最陡峭部分的密度标尺-长度。当这个参数超过一个临界值(主要由环形磁场的强度决定)时，就会发生转变。根据这一参数预测的阈值与DIII-D中经历L-H跃迁的放电的边缘测量结果吻合得很好[J.L.Luxon，R.Anderson，F.Batty等，见1986年第11届等离子体物理和受控聚变研究会议论文集(国际原子能机构，维也纳，1987)，Vol.I，第159页]。由于边缘密度梯度标尺长度的不同，所观察到的相变随环向磁场反转的差异可以用这一临界参数来协调。该理论还为DIII-D中较低的阈值功率和粒子注入H模提供了可能的解释，从而提供了关于L-H跃迁的各种观测的统一图像。托卡马克中边缘湍流的剪切流动稳定化已经成为在高(H)限制模等离子体中观察到的限制改善的公认范例。给出了有限β等离子体中纬向流和场的产生结果。这个理论给出了一个从低到高(L-H)限制模分叉的判据，它与Te/Ln成正比，其中Te是电子温度，Ln是密度梯度最陡峭部分的密度标尺-长度。当这个参数超过一个临界值(主要由环形磁场的强度决定)时，就会发生转变。根据这一参数预测的阈值与DIII-D中经历L-H跃迁的放电的边缘测量结果吻合得很好[J.L.Luxon，R.Anderson，F.Batty等，见1986年第11届等离子体物理和受控聚变研究会议论文集(国际原子能机构，维也纳，1987)，Vol.I，第159页]。在此基础上，进一步讨论了它们在相变过程中的差异。
Shear flow stabilization of edge turbulence in tokamaks has been the accepted paradigm for the improvement in confinement observed in high (H) confinement mode plasmas. Results on the generation of zonal flow and fields in finite β plasmas are presented. This theory yields a criterion for bifurcation from low to high (L–H) confinement mode, proportional to Te/Ln, where Te is the electron temperature and Ln is the density scale-length at the steepest part of the density gradient. When this parameter exceeds a critical value (mostly determined by the strength of the toroidal magnetic field), the transition occurs. The predicted threshold based on this parameter shows good agreement with edge measurements on discharges undergoing L–H transitions in DIII-D [J. L. Luxon, R. Anderson, F. Batty et al., in Proceedings of the 11th Conference on Plasma Physics and Controlled Fusion Research, 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. I, p. 159]. The observed differences in the transitions with the reversal of the toroidal magnetic field are reconciled in terms of this critical parameter due to the differences in the density gradient scale-lengths in the edge. The theory also provides a possible explanation for lowered threshold power, pellet injection H modes in DIII-D, thereby providing a unified picture of the varied observations on the L–H transition.Shear flow stabilization of edge turbulence in tokamaks has been the accepted paradigm for the improvement in confinement observed in high (H) confinement mode plasmas. Results on the generation of zonal flow and fields in finite β plasmas are presented. This theory yields a criterion for bifurcation from low to high (L–H) confinement mode, proportional to Te/Ln, where Te is the electron temperature and Ln is the density scale-length at the steepest part of the density gradient. When this parameter exceeds a critical value (mostly determined by the strength of the toroidal magnetic field), the transition occurs. The predicted threshold based on this parameter shows good agreement with edge measurements on discharges undergoing L–H transitions in DIII-D [J. L. Luxon, R. Anderson, F. Batty et al., in Proceedings of the 11th Conference on Plasma Physics and Controlled Fusion Research, 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. I, p. 159]. The observed differences in the transitions with th...