Quasisymmetry (QS) is a hidden symmetry of the magnetic field strength, B, that confines charged particles effectively in a three-dimensional toroidal plasma equilibrium. Here, we show that QS has a deep connection to the underlying symmetry that makes solitons possible. Our approach uncovers a hidden lower dimensionality of B on a magnetic…

In this paper we follow up on the results from our previous publication (Lobsien et al 2018 Nucl. Fusion 58 106013), where it was found that stellarator coil design optimization can be substantially improved by using a stochastic optimisation approach. In that paper performance was quantified by lower (better) and more narrow (more robust)…