Gauss' Separation Algorithm for the Magnetic Field Decomposition of the SPARC PRD simulation

Abstract

A magnetic separation algorithm originally introduced by Gauss has been revisited in recent years with application to magnetically-confined fusion experiments. The main result offered by Gauss' Separation Algorithm~(GSA) is a magnetic field computation that enables the decomposition of the contributions due to sources internal and external to a bounded volume through the generalized Virtual-Casing Principle. The present work applies GSA to simulations of the SPARC Primary Reference Discharge and demonstrates its separation capability on all phases of the shot, including the ramp-up during which significant currents on the passive structures often complicate the reconstruction of plasma equilibria. Such early results suggest a promising new way to study ramp-ups, disruptions, and vertical displacement events without any specific modeling assumption. Envisaged applications include reading magnetic data from experimental diagnostics and producing a new set of signals without external contributions to be used by downstream equilibrium codes for improved accuracy or speed.