Astronomy Tea Talk
The actual source of coronal heating is one of the longest standing unsolved mysteries in all of astrophysics. The million degree corona requires a permanent heating mechanism, or the gas would cool down in about an hour. Solar physicists agree that this mechanism involves the SunĂ¢€™s magnetic field, but few agree on the details of how magnetic energy in translated into thermal energy. Coronal loops, their structure and sub-structure, their temperature and density details, and their evolution with time, hold the key to understanding this coronal heating mystery. A loop had always been thought of as a simple magnetic flux tube, where each position along the loop is characterized by a single temperature and density. Recent results, however, found that this simple picture could not explain the observations and a multi-thermal analysis was required. If we picture the loop as a tangle of magnetic strands instead of single flux tube, then the multi-thermal result is expected and even predicted by some classes of coronal heating models.