We describe in detail the eruptive prominence associated coronal mass ejection of August 5, 1980, as seen in both the Solar Maximum Mission (SMM) coronagraph polarimeter and the Mauna Loa Observatory (MLO) K coronameter and prominence monitor. This event gives us the first detailed look at the propagation of a “depletion” transient into the outer corona. The event begins in the MLO K coronameter as a rising depletion of material, but appears later in the SMM coronagraph as an ordinary coronal mass ejection with a three‐part structure: a bright core within a dark lunette surrounded by a bright featureless “loop.” A joint time‐height plot of the major structures of the eruption seen by both instruments suggests that we can associate the three‐part structure in the outer corona with features in the low corona (prominence, prominence cavity, outer bright front). We argue from its observed mass that the leading loop in the SMM field of view is probably material that was in the background corona before the event. We suggest that this material has been displaced and set into motion by the rising “cavity.” One “leg” of the transient as seen by the SMM instrument is strongly bowed away from the bright core or prominence; this is in contrast to the straight, radial legs seen after Skylab mass ejections.

We describe and analyze in detail the coronal mass ejection of 18 August 1980, using images from the coronagraph on the Solar Maximum Mission (SMM) satellite. The event occurred at the site of a large coronal helmet streamer and evolved into the three‐part structure of a bright frontal shell, followed by a relatively dark space surrounding a bright filamentary core as seen in many mass ejections of the SMM epoch. The bright core can be identified as material from a prominence whose eruption was observed from the ground; this identification is based on (1) the looplike and filamented appearance of the core, (2) its motion along a trajectory that is a good extrapolation of the motion deduced from ground‐based observations of the prominence eruption, and (3) direct observations of Hα emission when the core is in the coronagraph field of view. The mass of the frontal shell is equal to that of the coronal helmet streamer (to the ∼30% accuracy with which mass estimates can be made), indicating that the shell is the coronal material previously in the helmet streamer, displaced and set into motion by the erupting prominence and surrounding cavity. The mass ejected in the bright core (or prominence) is estimated to be ∼50% larger than the “coronal” material in the frontal loop. The total mass of 2.5×1015 g and energy of 5×1031 ergs estimated for this mass ejection are both greater than in typical ejections of the Skylab era but are comparable to the average mass and energy in an interplanetary shock wave.

Sixty‐five coronal mass ejections have been identified in a systematic examination of white‐light coronal images obtained between March and September 1980 by the coronagraph/polarimeter flown on the solar maximum mission spacecraft. These ejections were more uniformly distributed in position angle (or “projected” solar latitude) than the similar events observed during the Skylab mission in 1973–1974; 27% of the solar maximum mission mass ejections were centered at positions more than 45° from the solar equator. The average rate of occurrence of the observed mass ejections for the entire solar maximum mission epoch, based on the assumption that one coronagraph image per spacecraft orbit is sufficient for detection, was 0.9±0.15 per 24‐hour day. Application of the same sampling assumption to the Skylab data set leads to a rate of 0.75 per 24‐hour day and thus a change in this rate from the Skylab era (on the declining phase of sunspot cycle 20) to solar maximum mission (near the maximum of sunspot cycle 21) of only ∼20%.

Observations of a number of helium triplet (~.210830, 4713, 4471, 3889, 4026) and hydrogea (H),, g, r/, 0) emission line intensities in six quiescent prominences are presented. The regions of prominence and neighboring corona were raster-scanned by the telescope, and all lines were measured concurrently at each point. The instrumental field of view was 5" • 20". The results are compared with previous observations and theory. In particular, the intensity of the 210830 emission relative to the other triplets is found to differ strongly from the predictions of the recent detailed calculations of Heasley et al. (1974) for model quiescent prominences.

We present SMM coronagraph/polarimeter observations of the coronal transient of March 15-16, 1980, which show a bright front convex toward the sun propagating out through the corona at 175 km s -•. A fan-shaped bright region connecting this front to the inner corona collapses into a narrow bright ray over the next few hours. We interpret these observations as resulting from the disconnection of magnetic loops from the underlying prominencelike loop structures seen rising earlier in the event.Other similar "inverted arches" exist in the C/P data but are usually seen with poorer temporal resolution.