Message from Jaroslav Dudik:
Dear all,
our paper on diagnostics of the non-Maxwellian kappa-distributions in a transient coronal loop observed by SDO/AIA and Hinode/EIS has been accepted for publication in The Astrophysical Journal. Please find the abstract and an ArXiV link below.
Title: Imaging and Spectroscopic Observations of a Transient Coronal Loop: Evidence for the Non-Maxwellian Kappa-Distributions
Authors: Jaroslav Dudik, Simon Mackovjak, Elena Dzifcakova, Giulio Del Zanna, David R. Williams, Marian Karlicky, Helen E. Mason, Juraj Lorincik, Pavel Kotrc, Frantisek Farnik, Alena Zemanova
Abstract: We report on the SDO/AIA and Hinode/EIS observations of a transient coronal loop. The loop brightens up in the same location after the disappearance of an arcade formed during a B8.9-class microflare three hours earlier. EIS captures this loop during its brightening phase as observed in most of the AIA filters. We use the AIA data to study the evolution of the loop, as well as to perform the DEM diagnostics as a function of kappa. Fe XI--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 257.772A selfblend, we diagnose kappa < 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 κ, all combinations of ratios of line intensities converge to the observed values, confirming the diagnosed kappa ≲ 2. These results represent the first positive diagnostics of kappa-distributions in the solar corona despite the limitations imposed by calibration uncertainties.
My best regards, Jaro
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