Uncovering the Birth of a Coronal Mass Ejection from Two-Viewpoint SECCHI Observations

TL;DR

This study uses two-viewpoint SECCHI observations to analyze the early stages of a fast CME, revealing magnetic evacuation, collapsing loops, and hot core formation, supporting the standard flare-CME model.

Contribution

It provides detailed 3D analysis of CME initiation, highlighting the role of collapsing loops and hot structures, and confirms the standard flare-CME model with multi-viewpoint EUV data.

Findings

Detection of collapsing loops indicating magnetic evacuation

Observation of a hot core structure in the CME

Agreement with the standard flare-CME model

Abstract

We investigate the initiation and formation of Coronal Mass Ejections (CMEs) via detailed two-viewpoint analysis of low corona observations of a relatively fast CME acquired by the SECCHI instruments aboard the STEREO mission. The event which occurred on January 2, 2008, was chosen because of several unique characteristics. It shows upward motions for at least four hours before the flare peak. Its speed and acceleration profiles exhibit a number of inflections which seem to have a direct counterpart in the GOES light curves. We detect and measure, in 3D, loops that collapse toward the erupting channel while the CME is increasing in size and accelerates. We suggest that these collapsing loops are our first evidence of magnetic evacuation behind the forming CME flux rope. We report the detection of a hot structure which becomes the core of the white light CME. We observe and measure unidirectional flows along the erupting filament channel which may be associated with the eruption process. Finally, we compare these observations to the predictions from the standard flare-CME model and find a very satisfactory agreement. We conclude that the standard flare-CME concept is a reliable representation of the initial stages of CMEs and that multi-viewpoint, high cadence EUV observations can be extremely useful in understanding the formation of CMEs.