Modeling Nanoflare Heating in Solar Coronal Active Regions

Monday, 15 December 2014
Joel C Allred and Vladimir Airapetian, NASA Goddard Space Flight Center, Greenbelt, MD, United States
High spatial resolution images of corona active regions (AR) obtained by Hinode, TRACE, SDO, and more recently Hi-C have demonstrated that the solar corona is structured into non-uniform bundles of magnetic loops heated to temperatures exceeding 5 MK. Nanoflare heating is a leading explanation for these observed high temperatures. Here we present results from a parameter study modeling the temperature and density structure of ARs using an impulsive nanoflare heating model. To estimate the coronal magnetic field, we have performed non-linear force free field (NLFFF) extrapolations on HMI vector magnetograms. We have traced field lines in closed field regions to obtain more than 12,000 individual flux tubes and have simulated nanoflares within each of these using a 1D hydrodynamic code. We have varied the energy released during the nanoflares as a function of magnetic field strength, loop length, flare duration and frequency. From the simulations, we can construct 3D models of the EUV/SXR emission produced by the ARs. We compare the simulated emission with that observed by AIA to constrain the heating parameters.