论文标题
具有非均匀磁剪的Tokamaks的局部陀螺仪模拟
Local gyrokinetic simulations of tokamaks with non-uniform magnetic shear
论文作者
论文摘要
在这项工作中，我们将标准通量管仿真域修改为包括任意离子gyroradius尺度变化，以安全系数的径向谱。为了确定如何适当地包含这种修改，我们添加了一个强大的离子gyroradius尺度源（灵感来自电子回旋电流驱动器）到fokker-Planck方程中，然后执行多尺度分析，以区分由源源源驱动的快速电子与慢散装热电子驱动的快速电子。这使我们能够系统地得出陀螺仪模型所需的更改。我们发现将离子和电子平行流沿修改的场线调节的新术语。这些术语已在陀螺仪代码中成功实施（同时保留了典型的傅立叶表示形式），该术语可以对非单调的安全因子概况和相关的剪切剪切进行通量管研究。作为一个说明性的例子，我们研究了具有正分和负三角形等离子体塑形的Tokamaks，发现轮廓剪切的重要性不会受到形状变化的显着影响。
In this work, we modify the standard flux tube simulation domain to include arbitrary ion gyroradius-scale variation in the radial profile of the safety factor. To determine how to appropriately include such a modification, we add a strong ion gyroradius-scale source (inspired by electron cyclotron current drive) to the Fokker-Planck equation, then perform a multi-scale analysis that distinguishes the fast electrons driven by the source from the slow bulk thermal electrons. This allows us to systematically derive the needed changes to the gyrokinetic model. We find new terms that adjust the ion and electron parallel streaming to be along the modified field lines. These terms have been successfully implemented in a gyrokinetic code (while retaining the typical Fourier representation), which enables flux tube studies of non-monotonic safety factor profiles and the associated profile shearing. As an illustrative example, we investigate tokamaks with positive versus negative triangularity plasma shaping and find that the importance of profile shearing is not significantly affected by the change in shape.
