First results of Magnetic Field Decomposition of SPARC simulations using Gauss' Separation Algorithm*

Gauss' Separation Algorithm (GSA), first introduced by Gauss in 1839 while tackling terrestrial magnetism and later exploited in many fields including planetary sciences, has been revisited in recent years and applied to plasma physics and tokamak experiments.

The main result offered by GSA is a magnetic field computation that enables the separation of the contributions due to sources internal and external to a bounded volume.

The present work applies such a generalized Virtual-Casing principle to simulations of the SPARC Primary Reference Discharge and demonstrates the separation capability of the algorithm on all phases of the shot, including the ramp-up during which consistent currents on the passive structures often complicate the modeling of plasma equilibria.

The magnetic field information is furthermore realistically projected onto a discrete mapping of the inner wall of the vacuum vessel that follows the current design of the SPARC magnetic diagnostics.

Such encouraging result suggests a promising new way to study ramp-ups, disruptions, and VDEs without any specific modeling assumption.

An example workflow might consist in preprocessing magnetic data to exclude external current contributions for further consumption by established reconstruction codes or control algorithms.