论文标题
直接计算Boozer坐标中的磁表面和准对称的线圈优化的线圈优化
Direct computation of magnetic surfaces in Boozer coordinates and coil optimization for quasi-symmetry
论文作者
论文摘要
我们提出了一种新方法，以计算在真空磁场的酒杯坐标中进行参数化的磁表面。我们还建议在计算的表面上进行准对称的度量，并使用它来设计线圈，该线圈在这些表面上产生准对称的磁场。在设计问题中还控制着场的旋转变换和线圈的复杂度度量。 使用伴随方法，我们能够获得此优化问题的分析导数，从而产生有效的基于梯度的算法。从为大量体积的嵌套磁体表面展示嵌套的磁性表面的初始线圈集开始，我们的方法迅速收敛到具有出色的准对称性和低粒子损耗的线圈系统。特别是对于低复杂性线圈，与从标准的两阶段方法获得的线圈相比，我们能够显着提高性能，例如，〜减少了融合产生的α粒子的损失，其融合产生的α颗粒的损失从$ 17.7 \％\％\％$ $ $ $ 6.6 \％\％。我们还用alpha损失<$ 1 \％$和新古典传输幅度$ε_ {\ mathrm {eff}}^{3/2} $小于$ 5 \ times 10^{ - 9} $小了
We propose a new method to compute magnetic surfaces that are parametrized in Boozer coordinates for vacuum magnetic fields. We also propose a measure for quasi-symmetry on the computed surfaces and use it to design coils that generate a magnetic field that is quasi-symmetric on those surfaces. The rotational transform of the field and complexity measures for the coils are also controlled in the design problem. Using an adjoint approach, we are able to obtain analytic derivatives for this optimization problem, yielding an efficient gradient-based algorithm. Starting from an initial coil set that presents nested magnetic surfaces for a large fraction of the volume, our method converges rapidly to coil systems generating fields with excellent quasi-symmetry and low particle losses. In particular for low complexity coils, we are able to significantly improve the performance compared to coils obtained from the standard two-stage approach, e.g.~reduce losses of fusion-produced alpha particles born at half-radius from $17.7\%$ to $6.6\%$. We also demonstrate 16-coil configurations with alpha loss < $1\%$ and neoclassical transport magnitude $ε_{\mathrm{eff}}^{3/2}$ less than approximately $5\times 10^{-9}.$
