Global simulations of ion turbulence with magnetic shear reversal
Global simulations of ion turbulence with magnetic shear reversal
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DOI：
10.1063/1.1367320
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发表时间：
2001-05
影响因子：
2.2
通讯作者：
X. Garbet;C. Bourdelle;G. Hoang;P. Maget;S. Benkadda;P. Beyer;C. Figarella;I. Voitsekovitch;O. Agullo;N. Bian
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文献类型：
--
作者：
X. Garbet;C. Bourdelle;G. Hoang;P. Maget;S. Benkadda;P. Beyer;C. Figarella;I. Voitsekovitch;O. Agullo;N. Bian
本文介绍了反向磁剪切托卡马克装置中静电离子湍流的三维流体全局模拟结果。结果表明，在磁剪切反转的位置出现了输运势垒。这是由于在该区域中谐振表面的稀疏。出于同样的原因，当安全系数的最小值是一个简单的有理数时，障碍更加明显。速度剪切效应使势垒变宽。研究还发现，大规模的输运事件几乎不跨越输运屏障。最后，湍流产生了大量的环形旋转。这种旋转在磁剪切反转的位置处改变其符号，正如从雷诺应力的准线性估计所预期的那样。
This paper presents the results of three-dimensional fluid global simulations of electrostatic ion turbulence in tokamaks with reversed magnetic shear. It is found that a transport barrier appears at the location of magnetic shear reversal. This is due to a rarefaction of resonant surfaces in this region. For the same reason, the barrier is more pronounced when the minimum of the safety factor is a simple rational number. The barrier is broadened by velocity shear effects. It is also found that large-scale transport events hardly cross a transport barrier. Finally, a significant amount of toroidal rotation is generated by the turbulence. This rotation changes its sign at the position of magnetic shear reversal, as expected from a quasi-linear estimate of the Reynolds stresstensor.