Authors: Aparna V., Sanjiv Tiwari, Navdeep Panesar, Ronald Moore, Bart De Pontieu, Thomas Wiegelmann, Brian Welsch

Based on the results from Tiwari et al. 2017, we investigate the importance of magneto-convection in heating active region coronal loops. Tiwari et al. found via SDO/AIA observations and NLFFF extrapolations that loops connecting sunspot umbrae are invisible in EUV images and those with one footpoint in sunspot umbra or penumbra and the other in opposite-polarity sunspot penumbra or plage regions, are seen as bright and hot loops. They conclude that a combination of the magnetic field strength of the regions the loops are rooted in and the convective freedom of the regions play an important role in determining the amount of heating in these loops.

The aim of our present study is to understand the statistical significance of the above findings. We select a sample of active regions of three kinds – those containing a pair of sunspots, those with a sunspot in the leading polarity but not a fully developed sunspot in the trailing polarity, and those that have no sunspot in any polarity. Using SDO/AIA images, we obtain the time frames of the images where the active regions are somewhat steady over a 48-hour time period, without any eruptions or flare-like bursts beyond GOES B-class flares. We select the instances where bright loops are present and choose the nearest HMI/SHARP vector magnetograms in time to perform NLFFF extrapolations using the method of Weigelmann et al. 2004. We also perform differential emission measure calculations over these AIA timeframes to verify the temperature characteristics. We quantify the convective freedom in the general locations of the loop footpoints by studying the photospheric flows in the respective regions by applying local correlation tracking using Fisher and Welsch (2008).