发表机构
Princeton Plasma Physics Laboratory; ITER Organization; Jubilee Development（普林斯顿等离子体物理实验室; 国际热核聚变实验堆组织; Jubilee发展公司）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对全 f 陀螺动力学模拟中初始瞬态问题，提出用新初始化方案，利用轴对称模拟的松弛粒子分布，经相空间平滑后用于全湍流模拟，应用于相关案例显著抑制瞬态、降噪声并减求解时间。
AI 中文摘要
全 f 五维陀螺动力学模拟对于自洽研究偏滤器托卡马克等离子体边缘区域的多尺度、多物理输运至关重要。然而，传统的局部麦克斯韦分布初始化通常会产生大幅瞬态，尤其是测地声模（GAMs）。在等离子体边缘，由于陡峭的剖面梯度、强径向电场和高安全因子，这些瞬态尤为严重，且会增加达到饱和湍流状态所需的计算时间。为解决此问题，我们提出了一种全 f XGC 代码的新初始化方案，该方案使用从计算成本低的轴对称模拟中获得的松弛粒子分布。在将分布转移到全湍流模拟之前，应用相空间平滑以减少粒子噪声，同时保留其新经典结构。应用于旋风基础案例和 ASDEX 升级 I 模放电表明，瞬态 GAMs 得到了显著抑制，粒子噪声降低，求解时间大幅减少。
英文摘要
Total-f five-dimensional gyrokinetic simulations are essential for self-consistent studies of multiscale, multiphysics transport in the edge region of diverted tokamak plasmas. However, conventional initialization with a local Maxwellian distribution often generates large-amplitude transients, particularly geodesic acoustic modes (GAMs). These transients are especially severe in the plasma edge because of steep profile gradients, strong radial electric fields, and high safety factors, and they can interfere with early-time turbulence and transport diagnostics. To address this problem, we present a new initialization scheme for the total-f XGC code that uses a relaxed particle distribution obtained from a computationally inexpensive axisymmetric simulation. Before the distribution is transferred to the full turbulence simulation, phase-space smoothing is applied to reduce particle noise while preserving its neoclassical structure. Simulations of the Cyclone Base Case and an ASDEX Upgrade I-mode discharge show that the method reduces particle noise and substantially suppresses initialization-driven transients.
