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arXiv 2406.16613physics.plasm-ph
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使用具有演化背景的delta-f粒子云网格方法在混合TEM/ITG区制中进行回旋动理学通量驱动模拟

Gyrokinetic flux-driven simulations in mixed TEM/ITG regime using a delta-f PIC scheme with evolving background

Moahan Murugappan, Laurent Villard, Stephan Brunner, Giovanni Di Giannatale, Ben Fynney McMillan, Alberto Bottino

AI总结:

本文提出将delta-f粒子云网格方法中的固定背景分布改为时间演化的麦克斯韦分布,以解决长时间通量驱动回旋动理学模拟中剖面显著演化导致的delta-f假设失效问题,在保持低采样噪声的同时以更少标记粒子获得数值收敛的准稳态结果。

摘要:

在使用粒子云网格框架进行全局回旋动理学湍流模拟的背景下,当确定与给定源相对应的准稳态剖面时,验证具有固定背景分布的delta-f假设变得具有挑战性,因为在长时间尺度上等离子体剖面可能显著演化。通过将背景视为具有时间相关密度和温度剖面的时间演化麦克斯韦分布,delta-f方案所提供的低相对采样噪声优势被证明得以保留。实现这种自适应方案来模拟托卡马克等离子体中的静电无碰撞通量驱动湍流,显示出较小且不增加的采样噪声水平,而在固定背景方案下噪声水平将无限增加。此外,自适应方案允许以少得多的标记粒子数达到数值收敛的准稳态结果。

英文摘要:

In the context of global gyrokinetic simulations of turbulence using a Particle-In-Cell framework, verifying the delta-f assumption with a fixed background distribution becomes challenging when determining quasi-steady state profiles corresponding to given sources over long time scales, where plasma profiles can evolve significantly. The advantage of low relative sampling noise afforded by the delta-f scheme is shown to be retained by considering the background as a time-evolving Maxwellian with time-dependent density and temperature profiles. Implementation of this adaptive scheme to simulate electrostatic collisionless flux-driven turbulence in tokamak plasmas show small and non-increasing sampling noise levels, which would otherwise increase indefinitely with a stationary background scheme. The adaptive scheme furthermore allows one to reach numerically converged results of quasi-steady state with much lower marker numbers.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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