[Loops] [1106.1591] Solar Dynamics Observatory discovers thin high temperature strands in coronal active regions

[Alan Gabriel]

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 at ias.u-psud.fr


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