A process specific to the dynamics of the heavy impurities in turbulent tokamak plasmas is found and analysed. We show that the parallel stochastic acceleration is strongly coupled to the perpendicular transport and generates a radial pinch velocity. The interaction is produced with the hidden drifts, a quasi-coherent component of the motion that consists of a pair of average radial velocities in opposite directions. The parallel acceleration breaks this symmetry and yields a radial average velocity that can be in the inward or outward direction. The transport of the tungsten ions in three-dimensional turbulence is analysed in the frame of a test particle model using numerical simulations. The results show that the acceleration induced pinch can be important for W impurity transport in present days tokamaks and in ITER.

中文翻译：

---

湍流托卡马克等离子体中平行加速对重杂质输运的影响

发现并分析了湍流托卡马克等离子体中重杂质动力学的特定过程。我们表明平行随机加速度与垂直传输强烈耦合并产生径向收缩速度。相互作用是由隐藏漂移产生的，这是一种运动的准相干分量，由一对相反方向的平均径向速度组成。平行加速度打破了这种对称性，并产生一个径向平均速度，可以是向内或向外的方向。钨离子在三维湍流中的传输在测试粒子模型的框架中使用数值模拟进行分析。结果表明，加速度引起的收缩对于当今托卡马克和 ITER 中的 W 杂质传输很重要。