Magnetic Activity and the Enhanced 5303 Å Emission in Solar Active Regions

Abstract

Analysis of the intensity maps of Fe xiv emission at λ=5303 A obtained from the observations of ground-based coronagraphs during the sunspot minimum period 1985 and 1986 shows the persistent presence of localized strong emissions. Typical emission intensities associated with the active regions were found to be about 5 to 20 times stronger than the unperturbed corona. Using Stanford magnetograms we identified strong magnetic field gradients in those active regions, with a minimum threshold gradient of 3 × 10−5 G km−1, associated with such strong emissions. From our sample we infer that the flux emergence within or in the vicinity of a persistent active region seems to play an important role in the activity associated with the enhancement in 5303 A emission.