Momentum losses by charge exchange with neutral particles in H-mode discharges at JET
Momentum losses by charge exchange with neutral particles in H-mode discharges at JET
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JET 的 H 模式放电中与中性粒子进行电荷交换造成的动量损失
DOI：
10.1088/0741-3335/53/6/065017
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发表时间：
2011
影响因子：
2.2
通讯作者：
K. Zastrow
中科院分区：
文献类型：
--
作者：
T. Versloot;P. D. de Vries;C. Giroud;M. Brix;M. von Hellermann;P. Lomas;D. Moulton;M. Mullane;I. Nunes;A. Salmi;T. Tala;I. Voitsekhovitch;K. Zastrow
在 JET 中研究了中性密度背景对环形角动量和动能分布的影响。在同等条件下，但随着平顶阶段气体燃料的增加，观察到边缘旋转和温度都会降低。电子密度的增加不足以补偿旋转和温度损失，使得能量和动量限制时间显着减少。观察到边缘局部模式行为受到中性流入增加的显着影响。使用简单的 1.5D 流体模型来定性捕获等离子体内的中性传输响应，然后使用碳的被动电荷交换 (CX) 发射的正向模型来获得校正的径向中性密度分布。研究发现，中性密度在边缘区域急剧衰减，在无燃料情况（Г0/ne ∼ 1.2 m s−1）和最大燃料情况（Г0/ne ∼ 2.5 m s−1）中具有相似的边缘强度。反向 B 操作的放电表现出与第一轨道效应和增加的壁相互作用相关的更高的归一化中性通量。在整个中性流入范围内，观察到基座热马赫数从 0.25 下降到 0.14。从解释模型中获得了由于多重 CX 相互作用而增加的中性渗透到基座顶部 (r/a ∼ 0.9)。在这些多重中性离子相互作用下，与 CX 能量损失相比，角动量对 CX 损失的影响更大。拖曳扭矩增加了总施加扭矩的 10%，而能量损失似乎更小。不幸的是，这种全局逼近方法的准确性是有限的；然而，估计的动量汇与解释观察到的全球能量和动量限制之间的差异所需的扭矩相当。
The effect of a neutral density background on the toroidal angular momentum and kinetic energy profiles has been investigated in JET. Under equivalent conditions but with increasing gas fuelling during the flat top phase, it has been observed that both the edge rotation and temperature decrease. The increase in electron density was not sufficient to compensate the rotation and temperature loss such that both energy and momentum confinement times are significantly reduced. The edge localized mode behaviour is observed to be significantly affected by the increased neutral influx. A simple 1.5D fluid model has been used to qualitative capture the neutral transport response within the plasma, followed by a forward model of the passive charge-exchange (CX) emission of carbon to obtain a corrected radial neutral density profile. It has been found that the neutral density is sharply attenuated over the edge region, with similar edge magnitudes in both the non-fuelled (Γ0/ne ∼ 1.2 m s−1) and maximum fuelled case (Γ0/ne ∼ 2.5 m s−1). Discharges with reversed-B operation exhibited even higher normalized neutral fluxes related to first orbit effects and increased wall interactions. Over the full neutral influx range, a decrease in pedestal thermal Mach number from 0.25 to 0.14 was observed. Increased neutral penetration up to the pedestal top (r/a ∼ 0.9) due to multiple CX interactions is obtained from the interpretive model. Under these multiple neutral–ion interactions, the impact on the CX loss of angular momentum is larger compared with the CX energy loss. The drag torque was seen to increase up to 10% of the total applied torque, while energy losses appeared to be smaller. The accuracy of this global approach method is unfortunately limited; however, the estimated momentum sink was found comparable to the torque required to explain the discrepancy between observed global energy and momentum confinement.
JT-60U H 模式等离子体中的三维中性输运模拟
DOI：
--
发表时间：
2008
期刊：
Journal of Physics:Conference Series
影响因子：
--
作者：
S.Ohdachi;et.al.;H.Urano;Y.Nakashima
通讯作者：
Y.Nakashima