CORONAL DENSITY AND TEMPERATURE STRUCTURE FROM COORDINATED OBSERVATIONS ASSOCIATED WITH THE TOTAL SOLAR ECLIPSE OF 1988 MARCH 18

This paper explores and compares diagnostics for temperature and density within large-scale structures of the inner corona based on cospatial and cotemporal spectrophotometric observations made at the time of the total solar eclipse of 1988 March 17/18. The basic data consists of the following: coronal soft X-ray images near 173 angstrom observed from a sounding rocket; eclipse observations of brightness of the K-corona in white light and in the green coronal line (5303 angstrom Fe XIV); and ground-based coronagraph observations of the green and red (6374 angstrom Fe X) coronal lines. The K-coronal observations alone provide a measure of electron density and of the scale-height temperature T(s), both as functions of position angle. A difficulty in atempting to characterize the state of the coronal plasma is that the temperature, absolute chemical abundances, and coronal density irregularity all affect the observed emission. However, in the analysis a determination of plasma temperature T can be derived unambiguously from the intensity ratios Fe XIV/XUV or Fe XIV/Fe X since all the emission lines come from the ionized state of Fe and the ratios are only weakly dependent on density. These temperatures and the densities found in well-defined large-scale coronal structures are discussed. We find the emission-line temperature to be high (local maxima) in the coronal structures with enhanced white-light emission and associated with new cycle high-latitude magnetic fields separated from the old cycle polar field of opposite polarity. Also the average of the ratio of T(s)/T over the entire range of position angle is roughly unity although the ratio is higher than unity (1.3-1.6) in the three most prominent streamers.