Near-axis expansion of weakly quasisymmetric fields to all orders: numerical implementation

The Garren-Boozer conundrum suggests that equilibrium with global quasi-symmetry (QS) probably does not exist under MHD with isotropic pressure. When expanded as power series of effective distance from magnetic axis, the governing equations become over-determined at the 3^rd order. [1] However, relaxing the pressure constraint from a scalar to a Maxwell stress tensor resolves the issue, form of equilibrium allowings the construction of equilibria with global weak QS to arbitrarily high orders. [2 - 4] We demonstrate the first numerical implementation of this expansion to all orders, which enables an as well as ongoing investigations of the convergence properties and optimal truncation of our asymptotic expansions, as well as Our code enables a deeper perspective on their implications for the equilibrium problem. Our tools enable a rapid exploration of the phase space of quasisymmetric configuration to which modern machine learning methods can be applied.