Impurity transport driven by ion temperature gradient turbulence in tokamak plasmas
Impurity transport driven by ion temperature gradient turbulence in tokamak plasmas
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DOI：
10.1063/1.3430639
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发表时间：
2010-06
影响因子：
2.2
通讯作者：
T. Fülöp;S. Braun;I. Pusztai
中科院分区：
文献类型：
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作者：
T. Fülöp;S. Braun;I. Pusztai
采用基于边界层解的半解析模型，分析了弱碰撞托卡马克等离子体中静电湍流驱动的杂质输运。扰动密度响应的解析表达式推导和用于确定稳定性边界和准线性粒子通量。对于中等的杂质电荷数Z，当有效电荷不变时，杂质电荷的增加对稳定性边界的影响很小;而对于较低的杂质电荷数Z，如果杂质的量不太小，则杂质的影响较大。定标的模式频率和准线性通量与电荷数，有效电荷，杂质密度规模的长度，和碰撞的确定和相比，准线性gyrokinetic模拟与GYRO产生非常好的协议。碰撞不影响模式频率，增长率，和杂质通量显着。本征频率和增长率仅弱依赖于Z和Zeff，但它们对杂质密度梯度尺度长度敏感。推导了零磁通杂质密度梯度的解析近似表达式，并讨论了其参数依赖性。
Impurity transport driven by electrostatic turbulence is analyzed in weakly collisional tokamak plasmas using a semianalytical model based on a boundary layer solution of the gyrokinetic equation. Analytical expressions for the perturbed density responses are derived and used to determine the stability boundaries and the quasilinear particle fluxes. For moderate impurity charge number Z, the stability boundaries are very weakly affected by the increasing impurity charge for constant effective charge, while for lower impurity charge the influence of impurities is larger, if the amount of impurities is not too small. Scalings of the mode frequencies and quasilinear fluxes with charge number, effective charge, impurity density scale length, and collisionality are determined and compared to quasilinear gyrokinetic simulations with GYRO resulting in very good agreement. Collisions do not affect the mode frequencies, growth rates, and impurity fluxes significantly. The eigenfrequencies and growth rates depend only weakly on Z and Zeff but they are sensitive to the impurity density gradient scale length. An analytical approximate expression of the zero-flux impurity density gradient is derived and used to discuss its parametric dependencies.