STEP中电磁湍流的全局 gyrokinetic 模拟

中文摘要 AI 辅助

本文针对概念性燃烧平顶运行点STEP [1]（STEP-EC-HD）开展梯度驱动的全局电磁 gyrokinetic 模拟，研究非局域效应如何影响有限β下电磁湍流的非线性饱和与输运。局域 gyrokinetic 模拟表明，包含δB∥对STEP中主导的混合动力学气球模（hKBMs）的不稳定性至关重要 [2]。本研究利用GENE [4]中实现的长波δB∥求解器 [3]，证明全局几何可准确捕捉线性模式谱，与一组局域通量管模拟结果吻合良好。全局框架重现了文献[5]中识别的hKBMs，而微撕裂模因径向尺度更短仍难以解析。非线性模拟揭示了向具有极大热通量状态的电磁转变的明确证据，与局域模拟及该拟议运行点的纬向流调控丧失的预测一致 [6]。这些发现确立了全局 gyrokinetics 捕捉类STEP等离子体中有限β动力学的能力，并为确定该转变的调控条件的后续工作提供了动力。

英文摘要

This paper presents gradient-driven global electromagnetic gyrokinetic simulations for a conceptual burning flat-top operating point of STEP [1], STEP-EC-HD, and investigates how non-local effects influence the nonlinear saturation and transport of the electromagnetic turbulence at finite $β$. Local gyrokinetic simulations have shown that including $δB_{\parallel}$ is essential for the dominant hybrid kinetic ballooning modes, or hKBMs, to be unstable in STEP [2]. Using the long-wavelength $δB_{\parallel}$ solver [3] implemented in GENE [4], this work demonstrates that the linear mode spectrum can be accurately captured in global geometry, which results in good agreement with an ensemble of local flux-tube simulations. The global framework reproduces the hKBMs identified in [5], while microtearing modes remain challenging to resolve due to their shorter radial scales. Nonlinear simulations reveal clear evidence of an electromagnetic transition to states with extremely large heat fluxes, consistent with local simulations and with the predicted loss of zonal-flow regulation for this proposed operating point [6]. These findings establish the capability of global gyrokinetics to capture finite-$β$ dynamics in STEP-like plasmas and motivate future work to identify the conditions governing this transition.

发表机构

• York Plasma Institute, University of York（约克等离子体研究所，约克大学）

机构由 AI 辅助整理，请以论文原文为准。