NSPF: a Non-Spherical Potential Field model for coronal magnetic field extrapolations

This repository is for the paper "A Non-Spherical Model for the Solar Coronal Magnetic Field" by Ziqi Wu. It is associated with the manuscript number AAS75232 In this study, we propose a novel Non-Spherical Potential Field (NSPF) model by employing the Finite Element Method to solve the Laplace equations with an irregular NSSS. This allows us to achieve more realistic open magnetic flux and coronal loop structures simultaneously. Our model consists of three layers: the potential field layer, the current sheet layer, and the interplanetary layer. The potential field and current sheet layers are separated by the NSSS; the current sheet and interplanetary layers are separated by the exit sphere, located at 10 R⊙. The potential field layer uses the synoptic magnetogram as the lower boundary input, and the potential field is calculated within. The current sheet layer takes the potential field layer solution as its lower boundary input, introduces current sheets by first enforcing a uniform positive polarity and then restoring the original polarities after computation, as in the SCS model. In the interplanetary layer, magnetic field lines follow the Parker spiral configuration.