Multi-species Gyro-kinetic Momentum Transport Modeling with the Trapped Gyro-Landau Fluid Model
Multi-species Gyro-kinetic Momentum Transport Modeling with the Trapped Gyro-Landau Fluid Model
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发表时间：
2011
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通讯作者：
G. Staebler;R. Waltz;J. Kinsey;W. Solomon;E. Belli
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作者：
G. Staebler;R. Waltz;J. Kinsey;W. Solomon;E. Belli
由于杂质离子密度小，通常对能量和粒子输运的贡献可以忽略不计。然而，杂质可以对环形动量输运做出重大贡献，因为它的规模与其质量乘以密度相同。因此，为了预测托卡马克中的动量输运，包括动力学杂质离子是至关重要的。首次将捕获回旋-朗道流体(TGLF)模型应用于多组分(电子、氚、碳6+)多通道(粒子、能量、动量)输运模拟实验。TGLF模型最近被扩展到包括科里奥利收缩[2]平行和E-B多普勒切变[3]。通过E-B多普勒频移中剪切引起的径向波数模型，将E-B多普勒切变包含在线性本征模波函数中。对于不同种类的等离子体，平行速度和平行速度剪切可以是不同的，因此可以包括抗磁和新经典极向流的贡献。包括环向旋转在内的TGLF预测等离子体轮廓的验证过程从L模和H模开始，并在非平衡中性束注入下进行。结果表明，当同时考虑主要离子和杂质时，TGLF所预测的放电动量输运水平与实验数据符合得很好。DIII-D托卡马克能够在任一环形方向上注入中性光束，因此收集了一系列扭矩范围内的数据。低扭矩数据对运输建模特别具有挑战性[4]。结果表明，即使在零外扭矩的情况下，TGLF也能预测净环向旋转。然而，这种“自发”自转依赖于许多类似大小的效应，包括涉及温度和密度的二阶导数的反磁漂移中的剪切。这使得低旋转轮廓的计算本质上是非局部的。在大扭矩下，动量输运不足以防止超音速圆环旋转破坏理论的低马赫数假设。添加高马赫数
Impurity ions usually make a negligible contribution to energy and particle transport because of their small densities. However, impurities can make a significant contribution to toroidal momentum transport since it scales like their mass times density. Hence, it is essential to include kinetic impurity ions in order to predict momentum transport in tokamaks. The first applications of the trapped gyro-Landau fluid (TGLF) model [1] to multispecies (electron, deuterium, carbon 6+) multi-channel (particle, energy, momentum) transport modeling of experiments will be presented. The TGLF model has recently been extended to include the Coriolis pinch [2] parallel and E B Doppler shear [3]. The E B Doppler shear is included in the linear eigenmode wavefunction through a model for the radial wavenumber induced by the shear in the E B Doppler shift. The parallel velocity and parallel velocity shear can be different for each species of the plasma so that the diamagnetic and neoclassical poloidal flow contributions can be included. The process of validating the TGLF predicted plasma profiles including the toroidal rotation starts with L-modes and H-modes with unbalanced neutral beam injection. It will be shown that the level of momentum transport predicted by TGLF for the discharges tested is in reasonable agreement with the data when both main ions and impurities are included. With the ability to inject neutral beams in either toroidal direction, the DIII-D tokamak has collected data over a range of torques. The low torque data is particularly challenging for transport modelling [4]. It will be shown that TGLF predicts a net toroidal rotation even with zero external torque. However, this “spontaneous” rotation depends on a multitude of effects of similar size including the shear in the diamagnetic drifts that involve the second derivative of the temperature and density. This makes the calculation of the low rotation profile intrinsically non-local. At high torque, the momentum transport is inadequate to prevent supersonic toroidal rotation violating the low mach number assumption of the theory. Adding the high mach number