Expansion of coronal mass ejections from the low to the outer corona

H. CREMADES

Simposio; VIII Brazilian Symposium in Space Geophysics and Aeronomy (SBGEA); 2021

Coronal mass ejections (CMEs) constitute the most spectacular dynamic events in the solar system, and are key players in determining space weather conditions. So far, it has been impossible to predict when a CME will erupt from the Sun, thus the best attempt at forecasting is to assess if and how they will impact Earth once erupted. Understanding how magnetic fields are organized within CMEs and how they evolve from the low corona into the heliosphere, is crucial. The stereoscopic-view images provided by the STEREO/SECCHI instrument suite in combination with images from Earth's perspective recorded by SDO/AIA and SOHO/LASCO provide a unique opportunity to study the morphological evolution of CMEs. The set of CMEs under study arises from an appropriate combination of spacecraft vantage points and CME propagation direction, which is helpful to reduce uncertainties in their forward modeling. These events are carefully analyzed as they originate low in the corona by means of simultaneous multi-viewpoint observations in the extreme UV, and followed up to the outer fields of view of the STEREO and SOHO coronagraphs. In particular, we examine how CMEs expand along their main symmetry axis and orthogonal to it, as well as the evolution of their global configuration.