Eruption of a flux rope on the disk of the sun: Evidence for the coronal mass ejection trigger?

The first evidence of acceleration of a flux rope from the disk of the Sun using the Coronal Diagnostic Spectrometer (CDS) on the Solar and Heliospheric Observatory (SOHO) is presented. A distinct blueshifted emission component (-480 km s(-1)) was observed by the EUV spectrometer on SOHO at the start of the impulsive phase of an X2.3 flare. There is a halo coronal mass ejection associated with this event. Based on a sequence of velocity measurements, we determine the acceleration of the erupting material. These results are supported by simultaneous EUV imaging data from the Transition Region and Coronal Explorer spacecraft, which shows the projected motion of the flux rope. The CDS spectra reveal an initial rapid acceleration phase (3.5 km s(-2)), followed by a transition to a more gradual acceleration (0.68 km s(-2)). This may indicate energy input via explosive reconnection.