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Spectroscopic Observations of Hot Lines Constraining Coronal Heating in Solar Active Regions View all abstracts by submitter

Spiros Patsourakos   Submitted: 2009-03-24 09:03

EUV observations of warm coronal loops suggest that they are bundles of unresolved strands that are heated impulsively to high temperatures by nanoflares. The plasma would then have the observed properties (e.g., excess density compared to static equilibrium) when it cools into the 1-2 MK range. If this interpretation is correct, then very hot emission should be present outside of proper flares. It is predicted to be vey faint, however. A critical element for proving or refuting this hypothesis is the existence of hot, very faint plasmas which should be at amounts predicted by impulsive heating. We report on the first comprehensive spectroscopic study of hot plasmas in active regions. Data from the EIS spectrometer on Hinode were used to construct emission measure distributions in quiescent active regions in the 1-5 MK temperature range. The distributions are flat or slowly increasing up to approximately 3 MK and then fall off rapidly at higher temperatures. We show that active region models based on impulsive heating can reproduce the observed EM distributions relatively well. Our results provide strong new evidence that coronal heating is impulsive in nature.

Authors: S. Patsourakos, J. A. Klimchuk
Projects: Hinode/EIS

Publication Status: ApJ 2009, in press
Last Modified: 2009-03-24 09:31
Go to main E-Print page  Seismology of a large solar coronal loop from EUVI/STEREO observations of its transverse oscillation  Hot Plasma in Non-Flaring Active Regions Observed by the Extreme-ultraviolet Imaging Spectrometer on Hinode  Edit Entry  Download Preprint  Delete Entry 

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