From Single Helical relaxed states to helical equilibria

TL;DR

This paper explores the connection between relaxed single helical states and helical equilibria in plasma physics, demonstrating the existence of marginally stable equilibria and comparing model predictions with experimental data.

Contribution

It establishes a link between relaxed states and helical equilibria, and demonstrates the existence of marginally stable equilibria using a perturbation approach.

Findings

Existence of marginally stable helical equilibria.

Model predictions align with experimental trends.

First order perturbation theory approximates the ohmic constraint.

Abstract

This paper analyzes the relationship between the Single Helical relaxed states studied in R. Paccagnella, Phys. of Plasmas 23 (2016) 092512 and the so called 'helical ohmic equilibria', i.e. plasma states that are solutions of the helical Grad Shafranov equation and that satisfy the constraint imposed by the Ohm law. The existence of marginally stable helical equilibria is clearly demonstrated, while the ohmic constraint is not exactly satisfied within the proposed first order perturbation theory. The model predictions are however satisfactorily compared with experimental trends.