论文标题
使用自动差异化优化有限构建恒星线圈
Optimized finite-build stellarator coils using automatic differentiation
论文作者
论文摘要
引入了一个新的恒星线圈设计代码，以优化有限构建线圈的位置和绕组方向。新代码（称为FocusAdd）在高维的非凸空间中执行基于梯度的优化。相对于有限构建线圈参数的衍生物很容易使用自动分化来计算。 FocusAdd使用傅立叶系列来参数在自由空间中的线圈位置，并对线圈绕组使用多丝近似。绕组包的方向用傅立叶系列进行参数化，并且也可以优化。发现了针对W7-X样恒星的优化有限构建线圈，并与丝状线圈结果进行了比较。相对于优化的丝状线圈，平均将优化有限的W7-X样线圈的最终位置移动约2.5mm。这些结果表明，应在具有低线圈公差的恒星优化时考虑有限构建效应。
A new stellarator coil design code is introduced that optimizes the position and winding pack orientation of finite-build coils. The new code, called FOCUSADD, performs gradient-based optimization in a high-dimensional, non-convex space. The derivatives with respect to parameters of finite-build coils are easily and efficiently computed using automatic differentiation. FOCUSADD parametrizes coil positions in free space using a Fourier series and uses a multi-filament approximation to the coil winding pack. The orientation of the winding pack is parametrized with a Fourier series and can be optimized as well. Optimized finite-build coils for a W7-X-like stellarator are found, and compared with filamentary coil results. The final positions of optimized finite-build W7-X-like coils are shifted, on average, by approximately 2.5mm relative to optimized filamentary coils. These results suggest that finite-build effects should be accounted for in the optimization of stellarators with low coil tolerances.
