[Loops] Evidence for non-Maxwellian Distributions, Dudik et al, 2015

[hm11 at damtp.cam.ac.uk]

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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http://arxiv.org/abs/1505.04333