OBSERVATIONAL CHARACTERISTICS OF CORONAL MASS EJECTIONS WITHOUT LOW-CORONAL SIGNATURES

Coronal Mass Ejections

A coronal mass ejection (CME) is an eruption of billions of tonnes of magnetically charged plasma from a star’s corona. The material ejected is sent into interplanetary space where it eventually dissipates. Should the material collide with a planet then that planet’s electro-magnetic field would be temporarily disrupted. If the Earth’s electro-magnetic field were disrupted by a large CME then p...

Composition of Coronal Mass Ejections

We analyze the physical origin of plasmas that are ejected from the solar corona. To address this issue, we perform a comprehensive analysis of the elemental composition of interplanetary coronal mass ejections (ICMEs) using recently released elemental composition data for Fe, Mg, Si, S, C, N, Ne, and He as compared to O and H. We find that ICMEs exhibit a systematic abundance increase of eleme...

Soft X-Ray Signatures of Coronal Ejections

We have a new view of the time behavior of the inner solar corona via the extensive soft X-ray observations of Yohkoh. These show many forms of expansion of coronal material, ranging from highly collimated structures (jets) to large-scale evacuations ("dimmings") of the diffuse corona. We review these effects, emphasizing those probably related to CMEs, and present a preliminary classification ...

Coronal Waves, Shock Formation and Coronal Mass Ejections

Low polarised emission from the core of coronal mass ejections

Aims. In white-light coronagraph images, cool prominence material is sometimes observed as bright patches in the core of coronal mass ejections (CMEs). If, as generally assumed, this emission is caused by Thomson-scattered light from the solar surface, it should be strongly polarised tangentially to the solar limb. However, the observations of a CME made with the SECCHI/STEREO coronagraphs on 3...