Gyrokinetic modelling of electron and boron density profiles of H-mode plasmas in ASDEX Upgrade
Gyrokinetic modelling of electron and boron density profiles of H-mode plasmas in ASDEX Upgrade
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DOI：
10.1088/0029-5515/51/2/023006
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发表时间：
2011-02
期刊：
影响因子：
3.3
通讯作者：
C. Angioni;R. McDermott;E. Fable;R. Fischer;T. Pütterich;F. Ryter;G. Tardini
中科院分区：
文献类型：
--
作者：
C. Angioni;R. McDermott;E. Fable;R. Fischer;T. Pütterich;F. Ryter;G. Tardini
本文给出了ASDEX Upgrade H模等离子体中电子密度和硼密度在半径中点处对数梯度的局部回旋动力学计算结果，并与实验结果进行了比较。实验结果表明，电子和硼的密度分布增加其峰值响应于增加中央电子回旋加热超过中性束注入（NBI）加热的背景。硼密度分布总是比限制区域中的电子密度分布更少峰值，并且在仅存在NBI加热的情况下是平坦的或甚至略微中空的。理论预测与实验结果吻合较好。该协议允许通过理论建模来识别导致观察到的依赖性的传输机制。特别是，所观察到的对数电子密度梯度增加，增加中央电子加热的解释由同时减少的向外的纯对流和向内的热扩散的增加。此外，还发现等离子体环向旋转速度及其径向梯度在湍流硼输运中起着不可忽视的作用，并允许预测硼峰随旋转速度的增加而减小，这与实验观测结果一致。
Local gyrokinetic calculations of the logarithmic gradients at mid-radius of both electron and boron densities in ASDEX Upgrade H-mode plasmas are presented and compared with the experimental observations. The experimental results show that both the electron and the boron density profiles increase their peaking in response to the addition of central electron cyclotron heating over a background of neutral beam injection (NBI) heating. The boron density profiles are always less peaked than the electron density profiles in the confinement region, and are flat or even slightly hollow in the presence of NBI heating only. The experimental behaviours are well reproduced by the theoretical predictions. The agreement allows the identification, through theoretical modelling, of the transport mechanisms responsible for the observed dependences. In particular, the observed increase in the logarithmic electron density gradient with increasing central electron heating is explained by a concurrent reduction of the outward pure convection and an increase in the inward thermodiffusion. In addition, it is found that the plasma toroidal rotation velocity and its radial gradient play a non-negligible role in the turbulent boron transport, and allow the prediction of a decrease in boron peaking with increasing rotation velocity, which is consistent with the experimental observations.