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Title: Forward modeling transient brightenings and microflares around an active region observed with Hi-C

Small-scale flare-like brightenings around active regions are among the smallest and most fundamental of energetic transient events in the corona, providing a testbed for models of heating and active region dynamics. In a previous study, we modeled a large collection of these microflares observed with Hinode/X-Ray Telescope (XRT) using EBTEL and found that they required multiple heating events, but could not distinguish between multiple heating events on a single strand, or multiple strands each experiencing a single heating event. We present here a similar study, but with extreme-ultraviolet data of Active Region 11520 from the High Resolution Coronal Imager (Hi-C) sounding rocket. Hi-C provides an order of magnitude improvement to the spatial resolution of XRT, and a cooler temperature sensitivity, which combine to provide significant improvements to our ability to detect and model microflare activity around active regions. We have found that at the spatial resolution of Hi-C (≈0.''3), the events occur much more frequently than expected (57 events detected, only 1 or 2 expected), and are most likely made from strands of the order of 100 km wide, each of which is impulsively heated with multiple heating events. These findings tend to support bursty reconnection as the cause ofmore » the energy release responsible for the brightenings.« less
Authors:
 [1] ;  [2]
  1. Now at National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States)
  2. Department of Physics, P.O. Box 173840, Montana State University, Bozeman, MT 59717-3840 (United States)
Publication Date:
OSTI Identifier:
22370420
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 794; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EXTREME ULTRAVIOLET RADIATION; HEAT EXCHANGERS; HEATING; SENSITIVITY; SIMULATION; SOUND WAVES; SPATIAL RESOLUTION; STELLAR CORONAE; STELLAR FLARES; SUN; TELESCOPES; TRANSIENTS; X RADIATION