Dual equilibrium in a finite aspect ratio tokamak

TL;DR

This paper introduces a dual equilibrium model in tokamaks combining paramagnetic and diamagnetic solutions to enhance plasma confinement and stability, offering a novel approach for designing efficient fusion devices.

Contribution

It presents a new dual equilibrium approach in tokamaks by combining two solutions of the Grad-Shafranov equation, improving stability and confinement.

Findings

Dual equilibrium structure exists within the same volume.

Combining equilibria enhances free-boundary mode stability.

The model balances large pressure gradients effectively.

Abstract

A new approach to high pressure magnetically-confined plasmas is necessary to design efficient fusion devices. This paper presents an equilibrium combining two solutions of the Grad-Shafranov equation, which describes the magnetohydrodynamic equilibrium in toroidal geometry. The outer equilibrium is paramagnetic and confines the inner equilibrium, whose strong diamagnetism permits to balance large pressure gradients. The existence of both equilibria in the same volume yields a dual equilibrium structure. Their combination also improves free-boundary mode stability.