THE GREEN LINE CORONA AND ITS RELATION TO THE PHOTOSPHERIC MAGNETIC-FIELD

Images of the green Line corona made with the LASCO Cl coronagraph on SOHO are analyzed by applying current-free extrapolations to the obser ved photospheric field. The Fe VIV lambda 5303 emission is Shown to be closely related to the underlying photospheric held strength. By mode ling the observed intensity patterns as a function of latitude and hei ght above the solar limb, we derive an approximate scaling law of the form n(foot) proportional to [B-foot](0.9), where n(foot) is the densi ty of the green line-emitting plasma and [B-foot] is the average held strength at the footprints of the coronal loop. The observed high-lati tude enhancements in the green line corona are attributed to the polew ard concentration of the large-scale photospheric held. The strongest such enhancements occur where the high-latitude unipolar fields become reconnected to active region flux at lower latitudes; the global emis sion pattern rotates quasi-rigidly at the rate of the dominant active region complex. The validity of the current-free approximation is asse ssed by comparing the topology of the observed and simulated green lin e structures.