Limb prominence eruption on 11 August 2000 as seen from ground- and space-based observations

We report on a prominence eruption as seen in Hα with the Crimean Lyot coronagraph, the global Hα network, and coronal images from the LASCO C2 instrument on board SOHO. We observed an Hα eruption at the northwest solar limb between 07:38:50 UT and 07:58:29 UT on 11 August 2000. The eruption originated in a quiet-Sun region and was not associated with an Hα filament. No flare was associated with the eruption, which may indicate that, in this case, a flux rope was formed prior to the eruption of the magnetic field. The Hα images and an Hα Dopplergram show a helical structure present in the erupted magnetic field. We suggest that the driving mechanism of the eruption may be magnetic flux emergence of magnetic flux injection. The limb Hα observations provide missing data on CME speed and acceleration in the lower corona. Our data show that the prominence accelerated impulsively at 5.5 km s^-2 and reached a speed slightly greater than 800 km s^-1 in a narrow region (h < 0.14 R _⊙) above the solar surface. The observations presented here also imply that, based only on a CME's speed and acceleration, it cannot be determined whether a CME is the result of a flare or an eruptive prominence.