Examination of coronal loops between quiescent active regions

Abstract

Active regions are dynamic and constantly evolving portions of the Sun, where the magnetic field emerges from beneath the solar surface and expands into the corona. Hot, dense plasma is aligned to these field lines and these brightly emitting structures are called coronal loops. These loops are the direct manifestations of solar magnetic fields, and thus observations of them can be used to investigate the structural evolution of the corona. As an active region is believed to be a single, isolated magnetic system, any flux linkage between multiple active regions must be formed in the corona post-emergence. Direct observations of new loops can provide evidence of this when using a two-active region system as a laboratory. Loops in such a system were examined in a variety of ways. First, interconnecting loops between two active regions over a 48-hour period were cataloged, testing the assumption that all interconnecting loops are new instance of flux linkage. The flux was significantly over-counted, which could be attributed either to the modeling technique used therein or the assumed structure (e.g., cross-sectional shape) of the loops. Both of these possibilities were tested by supplementing the catalog with data from a second observational line-of-sight (LOS). The results of this study contends that some loops have non-circular cross-sections, and some might even be less structured such that they do not have enough emission along the second LOS to be observed. Another possible reason for the overcounting of flux could be attributed to a loop brightening multiple times. We test this by looking at properties of loops from the same interconnecting region, but observed in different temperatures.