SOHO EIT OBSERVATIONS OF AN EARTH-DIRECTED CORONAL MASS EJECTION ON MAY 12, 1997/

An earth-directed coronal mass ejection (CME) was observed on May 12, 1997 by the SOHO Extreme ultraviolet Imaging Telescope (EIT). The CME; originating north of the central solar meridian, was later observed b y the Large Angle Spectrometric Coronagraph (LASCO) as a ''halo'' CME: a bright expanding ring centered about the occulting disk. Beginning at about 04:35 UT, EIT recorded several CME signatures, including dimm ing regions close to the eruption, post-eruption arcade formation, and a bright wavefront propagating quasi-radially from the source region. Each of these phenomena appear to be associated with the same eruptio n, and the onset time of these features corresponds with the estimated onset time observed in LASCO. We discuss the correspondence of these features as observed by EIT with the structure of the CME in the LASCO data.