Three-Dimensional MHD Simulation of the 2003 October 28 Coronal Mass Ejection: Comparison with LASCO Coronagraph Observations

TL;DR

This study uses 3D MHD simulations to model the 2003 October 28 CME, successfully reproducing observed features and providing insights into CME-shape formation and observational appearances in different coronagraphs.

Contribution

The paper presents a detailed 3D MHD simulation of a significant CME, matching LASCO observations and analyzing its appearance in STEREO images, highlighting the role of ambient solar wind.

Findings

Excellent agreement between simulated and observed CME morphology and brightness.

CME shape largely influenced by interaction with ambient solar wind.

Complex evolution of white-light images due to density structures passing through the Thomson sphere.

Abstract

We numerically model the coronal mass ejection (CME) event of October 28, 2003 that erupted from active region 10486 and propagated to Earth in less than 20 hours causing severe geomagnetic storms. The magnetohydrodynamic (MHD) model is formulated by first arriving at a steady state corona and solar wind employing synoptic magnetograms. We initiate two CMEs from the same active region, one approximately a day earlier that preconditions the solar wind for the much faster CME on the 28th. This second CME travels through the corona at a rate of over 2500 km s$^{-1}$ driving a strong forward shock. We clearly identify this shock in an image produced by the Large Angle Spectrometric Coronagraph (LASCO) C3, and reproduce the shock and its appearance in synthetic white light images from the simulation. We find excellent agreement with both the general morphology and the quantitative brightness of the model CME with LASCO observations. These results demonstrate that the CME shape is largely determined by its interaction with the ambient solar wind and may not be sensitive to the initiation process. We then show how the CME would appear as observed by wide-angle coronagraphs onboard the Solar Terrestrial Relations Observatory (STEREO) spacecraft. We find complex time evolution of the white-light images as a result of the way in which the density structures pass through the Thomson sphere. The simulation is performed with the Space Weather Modeling Framework (SWMF).