论文标题
用于局部陀螺仪仿真的非扭动通量管
A non-twisting flux tube for local gyrokinetic simulations
论文作者
论文摘要
局部陀螺仪模拟使用了一个磁场对准域，该域由于背景磁平衡的磁剪切而扭曲。但是，如果磁性剪切力很强和/或域很长，则扭曲可能会变得如此极端，以至于无法正确解决湍流。在这项工作中，我们得出并实施了“非扭转通量管”，这是一个局部仿真域，在所有平行位置都保持矩形。收敛和运行时测试表明，它可以比常规通量管更有效地计算热通量。对于一个测试案例，计算上的昂贵30倍，我们发现没有更昂贵的情况。当磁剪较高并且域包含至少两个湍流驱动器区域时，这是最有利的（例如，恒星模拟，基座模拟，带有多个poloidal旋转的Tokamak模拟）。此外，当磁性剪切较大时，它更准确地建模了板内平面。最后，我们展示了如何将非扭动的通量管推广到允许对模拟域的进一步优化和控制。
Local gyrokinetic simulations use a field-aligned domain that twists due to the magnetic shear of the background magnetic equilibrium. However, if the magnetic shear is strong and/or the domain is long, the twist can become so extreme that it fails to properly resolve the turbulence. In this work, we derive and implement the "non-twisting flux tube," a local simulation domain that remains rectangular at all parallel locations. Convergence and runtime tests indicate that it can calculate the heat flux more efficiently than the conventional flux tube. For one test case, it was 30 times less computationally expensive and we found no case for which it was more expensive. It is most advantageous when the magnetic shear is high and the domain includes at least two regions of turbulent drive (e.g. stellarator simulations, pedestal simulations, tokamak simulations with several poloidal turns). Additionally, it more accurately models the inboard midplane when the magnetic shear is large. Lastly, we show how the non-twisting flux tube can be generalized to allow further optimization and control of the simulation domain.
