FEQIS: A free-boundary equilibrium solver for integrated modeling of tokamak plasmas

TL;DR

FEQIS is a newly developed axisymmetric equilibrium solver designed for integrated tokamak plasma modeling, capable of solving the Grad-Shafranov and circuit equations with flexible configurations.

Contribution

It introduces a flexible, simplified numerical scheme for solving the Grad-Shafranov equation integrated with circuit equations, tailored for tokamak plasma modeling.

Findings

Successfully solves the Grad-Shafranov and circuit equations

Offers flexible circuit connection configurations

Provides a testable, simplified numerical scheme

Abstract

A new axisymmetric equilibrium solver has been written, called FEQIS (Flexible EQuIlibrium Solver), which purpose is to be used inside integrated modeling of tokamak plasmas. The FEQIS code solves the Grad-Shafranov equation and the "circuit" equations for the external coils and passive conducting structures that are toroidally connected. The code has been specifically equipped with flexibility in choice of circuit connections, and a stripped-down numerical scheme for the solution of the Grad-Shafranov equation through a structure of multi-level simplifications which can be tested against the required accuracy.