Connection between quasi-symmetric magnetic fields and anisotropic pressure equilibria in fusion plasmas

TL;DR

This paper explores the link between quasi-symmetric magnetic fields and anisotropic pressure equilibria in fusion plasmas, proposing a new paradigm to improve magnetic confinement design in stellarators.

Contribution

It reveals a fundamental connection between quasisymmetry and anisotropic pressure equilibria, challenging the belief that exact quasisymmetry is only locally achievable.

Findings

Existence of a deep physical connection between quasisymmetry and anisotropic pressure equilibria.

Potential to improve stellarator design by leveraging this connection.

Extension of equilibrium theory beyond isotropic pressure assumptions.

Abstract

The stellarator as a concept of magnetic confinement fusion requires careful design to confine particles effectively. A design possibility is to equip the magnetic field with a property known as quasisymmetry. Though it is generally believed that a steady-state quasisymmetric equilibrium can only be exact locally (unless the system has a direction of continuous symmetry such as the tokamak), we suggest in this work that a change in the equilibrium paradigm can ameliorate this limitation. We demonstrate that there exists a deep physical connection between quasisymmetry and magnetostatic equilibria with anisotropic pressure, extending beyond the isotropic pressure equilibria commonly considered.