arXivDaily arXiv每日学术速递 周一至周五更新
arXiv physics/0501039physics.plasm-phphysics.comp-ph
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等离子体边缘turbulence中杂质的反常扩散、聚集和箍缩

Anomalous diffusion, clustering, and pinch of impurities in plasma edge turbulence

M. Priego, O. E. Garcia, V. Naulin, J. Juul Rasmussen

摘要:

研究了等离子体边缘湍流中杂质粒子的湍流输运。杂质被建模为一个被动的流体平流的电和极化漂移,而周围的等离子体湍流建模使用二维长谷川-若谷范例电阻漂移波湍流。采用半拉格朗日拟谱格式,通过数值模拟研究了杂质的湍流输运特性。理想杂质湍流输运的扩散特性是通过对杂质喷吹演化的相对扩散分析来证明的。作为压缩性的结果,惯性杂质出现了额外的影响。首先,发现惯性杂质的密度与电漂移速度的涡度相关,即,杂质聚集在由杂质颗粒的电荷确定的精确取向的涡中。其次,发现了与杂质质荷比成线性关系的径向箍缩标度。通过对模型方程的分析,对这些观测结果进行了理论解释。

英文摘要:

The turbulent transport of impurity particles in plasma edge turbulence is investigated. The impurities are modeled as a passive fluid advected by the electric and polarization drifts, while the ambient plasma turbulence is modeled using the two-dimensional Hasegawa--Wakatani paradigm for resistive drift-wave turbulence. The features of the turbulent transport of impurities are investigated by numerical simulations using a novel code that applies semi-Lagrangian pseudospectral schemes. The diffusive character of the turbulent transport of ideal impurities is demonstrated by relative-diffusion analysis of the evolution of impurity puffs. Additional effects appear for inertial impurities as a consequence of compressibility. First, the density of inertial impurities is found to correlate with the vorticity of the electric drift velocity, that is, impurities cluster in vortices of a precise orientation determined by the charge of the impurity particles. Second, a radial pinch scaling linearly with the mass--charge ratio of the impurities is discovered. Theoretical explanation for these observations is obtained by analysis of the model equations.

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