In the strongly detached regimes, especially in future tokamak reactors, plasma in the divertor and in some special regions like vicinity of highly radiating X-point is strongly collisional. Ion gyrofrequency becomes less than Coulomb collision frequency and might be of the order of ion-neutral collision frequency. For such parameters, parallel and perpendicular ion diffusion and mobility caused by ion-neutral collision becomes important and can to large extent determine density profiles and currents distribution in the divertor. In the present article, plasma profiles in the vicinity of divertor plates were analysed. It is demonstrated that density profiles are determined by combination of parallel and perpendicular ambipolar diffusion. Results of analytic calculations are compared with Particle-In-Cell Monte-Carlo Collisions (PIC MCC) simulations of magnetized plasma and collisional transport of magnetized ions from quasi-neutral region to the material surface. Analytic expressions are compared with the results of particle in cell simulations done for different angles between magnetic field and material surface and different plasma parameters. Impact of velocity of neutral particles on ion fluxes and currents is also investigated. Consequences for divertor plasma typical for ITER and other future tokamak-reactors are discussed.

中文翻译：

---

高碰撞状态下的边缘托卡马克传输

在强分离状态下，特别是在未来的托卡马克反应堆中，偏滤器中的等离子体和一些特殊区域（如高辐射 X 点附近）是强烈碰撞的。离子回旋频率变得小于库仑碰撞频率并且可能是离子中性碰撞频率的量级。对于这些参数，由离子-中性碰撞引起的平行和垂直离子扩散和迁移率变得很重要，并且可以在很大程度上决定偏滤器中的密度分布和电流分布。在本文中，分析了偏滤器板附近的等离子体分布。证明了密度分布是由平行和垂直双极扩散的组合确定的。分析计算的结果与磁化等离子体的粒子内细胞蒙特卡罗碰撞 (PIC MCC) 模拟和磁化离子从准中性区域到材料表面的碰撞传输进行了比较。将解析表达式与在磁场和材料表面之间的不同角度和不同等离子体参数下进行的粒子在细胞模拟的结果进行比较。还研究了中性粒子的速度对离子通量和电流的影响。讨论了 ITER 和其他未来托卡马克反应堆典型的偏滤器等离子体的后果。将解析表达式与在磁场和材料表面之间的不同角度和不同等离子体参数下进行的粒子在细胞模拟的结果进行比较。还研究了中性粒子的速度对离子通量和电流的影响。讨论了 ITER 和其他未来托卡马克反应堆典型的偏滤器等离子体的后果。将解析表达式与在磁场和材料表面之间的不同角度和不同等离子体参数下进行的粒子在细胞模拟的结果进行比较。还研究了中性粒子的速度对离子通量和电流的影响。讨论了 ITER 和其他未来托卡马克反应堆典型的偏滤器等离子体的后果。