A Method for Data-Driven Simulations of Evolving Solar Active Regions

TL;DR

This paper introduces a data-driven simulation method for modeling the formation and evolution of solar active regions using magnetofriction, producing realistic flux rope ejections and synthetic coronal images.

Contribution

The paper presents a novel magnetofriction-based approach driven by real magnetogram data to simulate active region dynamics and generate synthetic EUV images.

Findings

Flux ropes are ejected due to loss of equilibrium in simulations.

Enhanced horizontal magnetic fields are observed near polarity inversion lines after flux rope ejections.

Synthetic coronal images resemble real AIA observations.

Abstract

We present a method for performing data-driven simulations of solar active region formation and evolution. The approach is based on magnetofriction, which evolves the induction equation assuming the plasma velocity is proportional to the Lorentz force. The simulations of active region coronal field are driven by temporal sequences of photospheric magnetograms from the Helioseismic Magnetic Imager (HMI) instrument onboard the Solar Dynamics Observatory (SDO). Under certain conditions, the data-driven simulations produce flux ropes that are ejected from the modeled active region due to loss of equilibrium. Following the ejection of flux ropes, we find an enhancement of the photospheric horizontal field near the polarity inversion line. We also present a method for the synthesis of mock coronal images based on a proxy emissivity calculated from the current density distribution in the model. This method yields mock coronal images that are somewhat reminiscent of images of active regions taken by instruments such as SDO's Atmospheric Imaging Assembly (AIA) at extreme ultraviolet wavelengths.