An elliptic expansion of the potential field source surface model

TL;DR

This paper introduces a numerical method to model the solar corona's magnetic field using an elliptical source surface, allowing for more accurate representations of the physical environment compared to traditional spherical models.

Contribution

It presents a novel numerical solver that computes the potential field with an elliptical source surface, relaxing the spherical constraint of existing models.

Findings

Elliptical source surface models show differences in magnetic field configurations.

The solver enables more flexible and accurate modeling of the solar corona.

Visualizations demonstrate the impact of elliptical deformation on magnetic field structure.

Abstract

Context. The potential field source surface model is frequently used as a basis for further scientific investigations where a comprehensive coronal magnetic field is of importance. Its parameters, especially the position and shape of the source surface, are crucial for the interpretation of the state of the interplanetary medium. Improvements have been suggested that introduce one or more additional free parameters to the model, for example, the current sheet source surface (CSSS) model. Aims. Relaxing the spherical constraint of the source surface and allowing it to be elliptical gives modelers the option of deforming it to more accurately match the physical environment of the specific period or location to be analyzed. Methods. A numerical solver is presented that solves Laplace's equation on a three-dimensional grid using finite differences. The solver is capable of working on structured spherical grids that can be deformed to create elliptical source surfaces. Results. The configurations of the coronal magnetic field are presented using this new solver. Three-dimensional renderings are complemented by Carrington-like synoptic maps of the magnetic configuration at different heights in the solar corona. Differences in the magnetic configuration computed by the spherical and elliptical models are illustrated.