Solar-Terrestrial Simulation in the STEREO Era: The January 24-25, 2007 Eruptions

TL;DR

This paper demonstrates the use of 3D MHD simulations to analyze and interpret CME observations from the STEREO spacecraft, revealing interactions and evolution of successive CMEs in the inner heliosphere.

Contribution

It introduces a combined observational and numerical modeling approach to study CME interactions and propagation, marking a new era of integrated solar-terrestrial research.

Findings

Successful simulation of CME interactions with structured solar wind

Detailed comparison between observations and synthetic images

Enhanced understanding of CME evolution in the inner heliosphere

Abstract

The SECCHI instruments aboard the recently launched STEREO spacecraft enable for the first time the continuous tracking of coronal mass ejections (CMEs) from the Sun to 1 AU. We analyze line-of-sight observations of the January 24-25, 2007 CMEs and fill the 20-hour gap in SECCHI coverage in January 25 by performing a numerical simulation using a three-dimensional magneto-hydrodynamic (MHD) code, the Space Weather Modeling Framework (SWMF). We show how the observations reflect the interaction of the two successive CMEs with each other and with the structured solar wind. We make detailed comparison between the observations and synthetic images from our model, including time-elongation maps for several position angles. Having numerical simulations to disentangle observational from physical effects, we are able to study the three-dimensional nature of the ejections and their evolution in the inner heliosphere. This study reflects the start of a new era where, on one hand, models of CME propagation and interaction can be fully tested by using heliospheric observations and, on the other hand, observations can be better interpreted by using global numerical models.