On the Three-Dimensional Configuration of Coronal Mass Ejections

H. CREMADES; V. BOTHMER; D. TRIPATHI

Nice, France

Congreso; European Geosciences Union - 1st General Assembly; 2004

EGU

Coronal mass ejections (CMEs) are a direct consequence of the dynamic nature of the Sun. Their origin, 3D structure and internal magnetic field configuration are to date not well understood. In this respect, the SOHO spacecraft has provided unprecedented data on CMEs since instruments switched on in 1996.After a careful investigation of the full set of LASCO (Large Angle Spectroscopic Coronagraph) observations from Jan 1996 to Dec 2002, structured CMEs have been identified. These are events which exhibit white-light fine structures, likely indicative of their internal magnetic field configuration and possible 3D structure. Their source regions in the low corona and photosphere have been deduced by analyzing data from the Extreme-Ultraviolet Imaging Telescope (EIT) and the Michelson Doppler Imager (MDI) onboard SOHO, and from ground-based Halpha measurements.According to the results here obtained, structured CMEs arise in a self-similar manner from pre-existing small scale loop systems, above regions of opposite magnetic polarities. From the characteristic pattern of the CMEs’ source regions in both solar hemispheres, a generic scheme is presented in which the projected white-light topology of a CME depends primarily on the orientation and position of the source region’s neutral line on the solar disk. Additional information about the white-light characteristics of the analyzed CMEs with respect to their source region properties is also provided.