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:提出了一种新的扰动和连续方法,用于计算和分析星际托卡马克的平衡状态。该方法在平衡条件$F \equiv J \times B - \nabla p = 0$周围展开级数形式得到,一个高效的算法用于计算二阶和三阶扰动的解。该方法已经在DESC星际托卡马克平衡代码中实现,使用自动微分来计算所需的导数。展示了使用该方法计算复杂的平衡、将托卡马克扰动为星际托卡马克以及在压力、旋转变换和边界形状上进行参数扫描所需时间仅为完整解决方案所需时间的一小部分的示例。