A new perturbation and continuation method is presented for computing and analyzing stellarator equilibria. The method is formally derived from a series expansion about the equilibrium condition $F \equiv J \times B - \nabla p = 0$, and an efficient algorithm for computing solutions to 2nd and 3rd order perturbations is developed. The method has been implemented in the DESC stellarator equilibrium code, using automatic differentiation to compute the required derivatives. Examples are shown demonstrating its use for computing complicated equilibria, perturbing a tokamak into a stellarator, and performing parameter scans in pressure, rotational transform and boundary shape in a fraction of the time required for a full solution.

翻译：本文提出了一种用于计算和分析仿星器平衡态的新微扰与延拓方法。该方法基于平衡条件$F \equiv J \times B - \nabla p = 0$的级数展开形式推导得到，并开发了高效算法用于计算二阶和三阶微扰的解。该方法已在DESC仿星器平衡代码中实现，利用自动微分技术计算所需的导数。示例展示了该方法在以下场景中的应用：计算复杂平衡态、将托卡马克扰动为仿星器构型，以及在压力、旋转变换和边界形状参数扫描中达到完整求解所需时间的数分之一。