A nice paper and an important contribution to the debate. But
the jury is still out. We may never resolve this without real
spectroscopic evidence of the very hot component. Where is our
future spectroscopy coming from??
Alan Gabriel
Le 09/06/2011 10:52, Fabio Reale a écrit :
Dear colleagues
please find at the following link the preprint of a work
accepted for publication on the ApJ Letters, showing new
strong evidence of finely-structured loops with impulsive
nanoflare activity in active regions:
http://arxiv.org/abs/1106.1591
The abstract is below.
Best regards
Fabio Reale
Solar Dynamics
Observatory discovers thin high temperature strands in
coronal active regions
Authors:
Fabio Reale, Massimiliano Guarrasi, Paola Testa, Edward E.
DeLuca, Giovanni
Peres, Leon Golub
Abstract:
One scenario proposed to explain the million degrees solar
corona is a finely-stranded corona where each strand is
heated by a rapid pulse. However, such fine structure has
neither been resolved through direct imaging observations
nor conclusively shown through indirect observations of
extended superhot plasma. Recently it has been shown that
the observed difference in appearance of cool and warm
coronal loops (~1 MK, ~2-3 MK, respectively) -- warm loops
appearing "fuzzier" than cool loops -- can be explained by
models of loops composed of subarcsecond strands, which are
impulsively heated up to ~10 MK. That work predicts that
images of hot coronal loops (>~6 MK) should again show
fine structure. Here we show that the predicted effect is
indeed widely observed in an active region with the Solar
Dynamics Observatory, thus supporting a scenario where
impulsive heating of fine loop strands plays an important
role in powering the active corona.
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Alan GABRIEL alan.gabriel@ias.u-psud.fr
Institut d'Astrophysique Spatiale tel : (33) 1 69 85 85 10
Batiment 121, Universite Paris XI fax : (33) 1 69 85 86 75
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