Evidence of a flux-rope model for corona mass ejections based on observations of the limb prominence eruption on 2002 January 4

We report on a prominence eruption as seen in Kanzelhöhe Solar Observatory Hα images, Solar and Heliospheric Observatory (SOHO) EUV Imaging Telescope (EIT) 195 Åimages, and coronal S OHO Large Angle Spectrometric Coronograph C2 images. Our data favor the flux-rope model for coronal mass ejections (CMEs), which suggests that a flux rope is formed long before the eruption. Our conclusion is based on a three-part structure of the pre-erupted configuration of the magnetic field and on the fact that the first Hα, SOHO BIT 195 Å brightenings occurred some 15 minutes after the filament began to ascend. The data also clearly demonstrate two rarely observed components of the standard flare model: (1) magnetic loops that overlay the pre-erupted filament and (2) magnetic field lines stretched vertically by the ascending filament. These field lines are compressed horizontally and move toward each other where they reconnect to form an apparently growing post-flare loop system.