Imaging and Spectroscopic Observations of a Transient Coronal Loop: Evidence for the Non-Maxwellian K Distributions

0450485 - ASÚ 2016 RIV US eng J - Journal Article
Dudík, Jaroslav - Mackovjak, Šimon - Dzifčáková, Elena - Del Zanna, G. - Williams, D.R. - Karlický, Marian - Mason, H. E. - Lörinčík, J. - Kotrč, Pavel - Fárník, František - Zemanová, Alena
Imaging and Spectroscopic Observations of a Transient Coronal Loop: Evidence for the Non-Maxwellian K Distributions.
Astrophysical Journal. Roč. 807, č. 2 (2015), 123/1-123/19. ISSN 0004-637X. E-ISSN 1538-4357
R&D Projects: GA ČR GAP209/12/1652
Institutional support: RVO:67985815
Keywords : radiation mechanisms * Sun * corona
Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics
Impact factor: 5.909, year: 2015

We report on the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) and Hinode/EUV Imaging Spectrograph (EIS) observations of a transient coronal loop. We use the AIA data to study the evolution of the loop, as well as to perform the differential emission measure (DEM) diagnostics as a function of kappa. The Fe XI-Fe XIII lines observed by EIS are used to perform the diagnostics of electron density and subsequently the diagnostics of kappa. Using ratios involving the Fe XI 257.772 angstrom self-blend, we diagnose kappa less than or similar to 2, i.e., an extremely non-Maxwellian distribution. Using the predicted Fe line intensities derived from the DEMs as a function of kappa, we show that, with decreasing kappa, all combinations of ratios of line intensities converge to the observed values, confirming the diagnosed kappa less than or similar to 2. These results represent the first positive diagnostics of kappa-distributions in the solar corona despite the limitations imposed by calibration uncertainties.
Permanent Link: http://hdl.handle.net/11104/0251794