Assessment of the strength of kinetic effects of parallel electron transport in the SOL and divertor of JET high radiative H-mode plasmas using EDGE2D-EIRENE and KIPP codes
Assessment of the strength of kinetic effects of parallel electron transport in the SOL and divertor of JET high radiative H-mode plasmas using EDGE2D-EIRENE and KIPP codes
复制标题
使用 EDGE2D-EIRENE 和 KIPP 代码评估 JET 高辐射 H 模式等离子体的 SOL 和偏滤器中平行电子传输的动力学效应强度
DOI：
10.1088/1361-6587/aae0a0
复制
发表时间：
2018
影响因子：
2.2
通讯作者：
A. Jaervinen
中科院分区：
文献类型：
--
作者：
A. Chankin;G. Corrigan;A. Jaervinen
采用等离子体外围的动力学代码（KIPP）来评估JET高辐射h模elm间等离子体刮擦层（SOL）和分流器中平行电子传递的动力学效应的重要性。从一个EDGE2D-EIRENE模拟案例中获得的等离子体参数曲线被用作KIPP运行的输入。剖面由粒子源和电源维持。KIPP生成了在分流靶处的电子分布函数、fe、平行功率通量、电子-离子热力、德拜鞘电位下降和电子鞘透射系数。对于主SOL的热通量，KIPP结果显示与经典（如Braginskii）通量的偏差系数通常为~ 1.5，有时高达2，通量限制在上游位置，而在导流器入口处附近通量增强。与此同时，在靠近分离矩阵的径向位置，在外靶处发现了非常大的热通量增强因子，可达10甚至更高，表明强烈的非局部热输运，热功率通量密度在高能处表现出尾部碰撞特征。然而，在这种极端条件下，导电功率通量对总功率通量的贡献大大减少，对流功率通量变得与导电功率通量相当，有时甚至超过导电功率通量。另一方面，已知主要由热电子和亚热电子决定的电子-离子热力，被发现与Braginskii公式（包括Zeff依赖）很好地一致。总的来说，KIPP结果表明，至少在这个模型中使用的等离子体条件下，动力学对平行电子传递有相当大的影响，但不是主要的影响。
The kinetic code for plasma periphery (KIPP) was used to assess the importance of the kinetic effects of parallel electron transport in the scrape-off layer (SOL) and divertor of JET high radiative H-mode inter-ELM plasma conditions with the ITER-like wall and strong nitrogen (N2) injection. Plasma parameter profiles along a magnetic field from one of the EDGE2D-EIRENE simulation cases were used as an input for KIPP runs. Profiles were maintained by particle and power sources. KIPP generated electron distribution functions, fe, parallel power fluxes, electron–ion thermoforces, Debye sheath potential drops and electron sheath transmission factors at divertor targets. For heat fluxes in the main SOL, KIPP results showed deviations from classical (e.g. Braginskii) fluxes by factors typically of ∼1.5, sometimes up to 2, with the flux limiting for more upstream positions and flux enhancement near entrances to the divertor. In the divertor, at the same time, for radial positions closer to the separatrix, very large heat flux enhancement factors of up to ten or even higher, indicative of a strong nonlocal heat transport, were found at the outer target, with heat power flux density exhibiting bump-on-tail features at high energies. Under such extreme conditions, however, contributions of conductive power fluxes to total power fluxes were strongly reduced, with convective power fluxes becoming comparable, or sometimes exceeding, conductive power fluxes. Electron–ion thermoforce, on the other hand, which is known to be determined mostly by thermal and subthermal electrons, was found to be in good agreement with Braginskii formulas, including the Zeff dependence. Overall, KIPP results indicate, at least for the plasma conditions used in this modelling, a sizable, but not dominant, effect of kinetics on parallel electron transport.