IMAGING AND SPECTROSCOPIC OBSERVATIONS OF A TRANSIENT CORONAL LOOP: EVIDENCE FOR THE NON-MAXWELLIAN κ-DISTRIBUTIONS

Journal Article · Fri Jul 10 00:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/807/2/123· OSTI ID:22522188

Dudík, Jaroslav; Mackovjak, Šimon; Dzifčáková, Elena; Karlický, Marian; Kotrč, Pavel; Fárník, František; Zemanová, Alena ^[1]; Del Zanna, Giulio; Mason, Helen E. ^[2]; Williams, David R. ^[3]; Lörinčík, Juraj ^[4]

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1. Astronomical Institute of the Academy of Sciences of the Czech Republic, Fričova 298, 251 65 Ondřejov (Czech Republic)
2. DAMTP, CMS, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)
3. University College London, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking, Surrey RH5 6NT (United Kingdom)
4. DAPEM, Faculty of Mathematics Physics and Computer Science, Comenius University, Mlynská Dolina F2, 842 48 Bratislava (Slovakia)

We report on the Solar Dynamics Observatory/Atmospheric Imaging Assembly (AIA) and Hinode/EUV Imaging Spectrograph (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 3 hr 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 differential emission measure (DEM) diagnostics as a function of κ. The Fe xi–Fe xiii lines observed by EIS are used to perform the diagnostics of electron density and subsequently the diagnostics of κ. Using ratios involving the Fe xi 257.772 Å self-blend, we diagnose κ ≲ 2, i.e., an extremely non-Maxwellian distribution. Using the predicted Fe line intensities derived from the DEMs as a function of κ, we show that, with decreasing κ, all combinations of ratios of line intensities converge to the observed values, confirming the diagnosed κ ≲ 2. These results represent the first positive diagnostics of κ-distributions in the solar corona despite the limitations imposed by calibration uncertainties.

• OSTI ID: 22522188
• Journal Information: Astrophysical Journal, Vol. 807, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CALIBRATION
CAPTURE
ELECTRON DENSITY
EXTREME ULTRAVIOLET RADIATION
GAMMA RADIATION
IRON IONS
SOLAR CORONA
SOLAR FLARES
SUN
TRANSIENTS
X RADIATION