William J. Wagner

Studies of the corona with the Solar Maximum Mission coronagraph/polarimeter

The visible wavelength Coronagraph/Polarimeter on the Solar Maximum Mission (SMM) spacecraft is providing data on the flare processes manifested by coronal transients and on the degree of disruption of the evolutionary corona at the present epoch of the solar activity cycle. Among our first results are the discovery of frequent H..cap alpha.. emission from remnants of eruptive prominences in the outer corona and first observations of Fe XIV line emisson to 3.2 R/sub sun/. In the early stages of transients, cavities less dense than the ambient corona are occasionally found trailing the transient loops, with the loops being relatively thick and structureless. Some 22 transients have been identified in the initial survey of 52 days of observations; from this sample our preliminary conclusion is that transients during the SMM era (near solar maximum) occur over a wider range of latitude than, but with about the same range of speeds as, transients during the Skylab era (near solar minimum).

The association of radio noise storm enhancements with the appearance of additional material in the corona

Visible light observations of the corona have been combined with radioheliograph observations at metric wavelengths to examine the dynamic behavior of the corona during and after noise storm onsets and enhancements. For the period studied, the occurrence of such radio events is systematically associated with the addition of coronal material in the vicinity of the radio source. Some of the events correspond to mass ejection transients, but they more frequently represent merely a brightening, which grows in 1 hour or less with the coronal region and remains dense and stable for several hours.

A white-light /Fe X/H-alpha coronal transient observation to 10 solar radii

Multi-telescope observations of the coronal transient of 15–16 April, 1980 provide simultaneous data from the Solar Maximum Mission Coronagraph/Polarimeter, the Solwind Coronagraph, and the new Emission Line Coronagraph of the Sacramento Peak Observatory. An eruptive prominence-associated white light transient is for the first time seen as an unusual wave or brightening in Fe xgl6374 (but not in Fe xivgl5303). Several interpretations of this fleeting enhancement are offered.The prominence shows a slowly increasing acceleration which peaks at the time of the Fe event. The white light loop transient surrounding the prominence expands at a well-documented constant speed to 10R⊙, with an extrapolated start time at zero height coincident with the surface activity.This loop transient exemplifies those seen above 1.7R⊙ in that leading the disturbance is a bright (Ne-enhanced) loop rather than dark. This is consistent with a report of the behavior of another eruptive event observed by Fisher and Poland (1981) which began as a density depletion in the lower corona, with a bright loop forming at greater altitudes. The top of the bright loop ultimately fades in the outer corona while slow radial growth continues in the legs.

A survey of current coronal visible line identifications

A literature search has been made pertaining to the identifications of coronal visible lines. Of over one hundred lines reported seen at eclipses, about forty identifications are widely quoted. Close scrutiny of the literature, however, reveals that only twenty of these identifications are not disputed by one or more authors.