Analysis of Inter-moss Loops in the Solar Transition Region with IRIS and SDO/AIA: Automatic Event Detection and Characterization

The transition region of the solar atmosphere is no longer believed to be exclusively a thin boundary layer connecting the chromosphere and the corona. Instead, the emission from this region is dominated by dynamic, low-lying loops with peak temperatures <1 MK. These loops also appear in AIA data due to the transition region spectral lines in the AIA passbands, but have not been studied with great detail. The IRIS instrument has resolved these loops both spatially and temporally. With an IRIS image cadence of approximately 10 seconds, we are able to study the evolution of these loops.

We have developed a technique to automatically identify events (i.e., brightenings) on a pixel-by-pixel basis applying a set of selection criteria. The pixels are then grouped according to their proximity in space and relative progression of the event. This method allows us to characterize their overall lifetime and the rate at which these events occur. Our current progress includes identification of these groups of events in IRIS data, determination of their existence in AIA data, and characterization based on a comparison between the two. If the same events appear in both IRIS and AIA data, it may suggest that the intrinsic transition region is not in local thermodynamic equilibrium. We present the results that follow each integral step in the analysis and provide a preliminary characterization of a few example events within our data set.