A coronal mass ejection (CME) is a significant release of plasma and accompanying magnetic field from the solar corona. CMEs often follow solar flares and are normally present during a solar filament (prominence) eruption. Generally, solar eruptions are often in the radial direction of the Sun, and one successful solar eruption in the low corona produces a single large-scale coronal mass ejection into the interplanetary space.

An interesting observational study on the generation of CME has been published by The Astrophysical Journal on August 21, which was performed by a joint solar group including solar physicists from Yunnan Observatories, Chinese Academy of Sciences and Yunnan Normal University.

The observation clearly indicated that two simultaneous radial propagating CMEs were dynamically associated with the eruption of a blowout jet that was driven by the eruption of a miniature filament. The CMEs firstly propagated non-radially during their initial stage in the low corona; after their interaction with a group of remote open magnetic field, they were deflected significantly by the open fields and became radially.

Detailed investigation indicates that one of the CMEs was evolved from the eruption of the miniature filament, while the other one was formed by the outward propagating plasma flows generated in the magnetic reconnection between the confining magnetic field of the miniature filament and the ambient open field lines.

"This finding not only confirms our previous works, but also provides new understanding on the formation and propagation behaviors of CMEs", the group leader Dr. SHEN Yuandeng said, "On the other hand, the formation mechanism and the deflection of the CMEs are also important for further theoretical study and the space weather forecast."