EIT AND LASCO OBSERVATIONS OF THE INITIATION OF A CORONAL MASS EJECTION

We present the first observations of the initiation of a coronal mass ejection (CME) seen on the disk of the Sun. Observations with the EIT experiment on SOHO show that the CME be an in a small volume and was i nitially associated with slow motions of prominence material and a sma ll brightening at one end of the prominence. Shortly afterward! the pr ominence was accelerated to about 100 km s(-1) and was preceded by a b right loop-like structure, which surrounded an emission void, that tra veled out into the corona at a velocity of 200-400 km s(-1). These thr ee components, the prominence, the dark void, and the bright loops are typical of CMEs when seen at distance in the corona and here are show n to be present at the earliest stages of the CME. The event was later observed to traverse the LASCO coronagraphs fields of view from 1.1 t o 30 RE.. Of particular interest is the fact that this large-scale eve nt, spanning as much as 70 deg in latitude, originated in a volume wit h dimensions of roughly 35'' (2.5 x 10(4) km). Further, a disturbance that propagated across the disk and a chain of activity near the limb may also be associated with this event as well as a considerable degre e of activity near the west limb.