标题： 托卡马克等离子体边缘层中的总流体压力不平衡 显示英文标题

标题： Total Fluid Pressure Imbalance in the Scrape-Off Layer of Tokamak Plasmas

摘要： 使用全动能漂移输运代码 XGCa 进行的模拟旨在探讨动力学效应对 DIII-D H 模等离子体边缘层（SOL）物理的影响。 XGCa 是一个总分布函数、磁流体力学代码，能够自洽地计算轴对称静电势和等离子体动力学，并包含蒙特卡洛中性粒子输运模块。 之前展示的 XGCa 结果显示出几个值得注意的特征，包括在 SOL 中沿磁场线的离子密度和压力的大范围变化，实验相关的 SOL 平行离子流动水平（马赫数约 0.5），在鞘层入口附近的离子分布不对称导致那里的亚声速流动，以及升高的鞘层电位 [R.M. Churchill, Nucl. Mater. & Energy, submitted]。 在本文中，我们详细探讨了 SOL 中的压力平衡问题，因为在模拟中观察到与简单总压力平衡（离子和电子静压之和加上离子惯性）存在较大偏差。 将表明，来自离子粘滞（由离子温度各向异性驱动）和中性源项的贡献可能都很显著，并应在 SOL 的平行动量方程中保留，但仍不足以解释 XGCa 模拟结果中观察到的流体压力不平衡。 显示英文摘要

摘要： Simulations using the fully kinetic neoclassical code XGCa were undertaken to explore the impact of kinetic effects on scrape-off layer (SOL) physics in DIII-D H-mode plasmas. XGCa is a total-f, gyrokinetic code which self-consistently calculates the axisymmetric electrostatic potential and plasma dynamics, and includes modules for Monte Carlo neutral transport. Previously presented XGCa results showed several noteworthy features, including large variations of ion density and pressure along field lines in the SOL, experimentally relevant levels of SOL parallel ion flow (Mach number~0.5), skewed ion distributions near the sheath entrance leading to subsonic flow there, and elevated sheath potentials [R.M. Churchill, Nucl. Mater. & Energy, submitted]. In this paper, we explore in detail the question of pressure balance in the SOL, as it was observed in the simulation that there was a large deviation from a simple total pressure balance (the sum of ion and electron static pressure plus ion inertia). It will be shown that both the contributions from the ion viscosity (driven by ion temperature anisotropy) and neutral source terms can be substantial, and should be retained in the parallel momentum equation in the SOL, but still falls short of accounting for the observed fluid pressure imbalance in the XGCa simulation results.