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

[Ed DeLuca]

Hi Alan,

  We have two "cunning plans":

(1) there is a rocket proposal for a new grazing incident spectrograph - 
Ken Kobayashi, Leon, Jonathan or Kelly can provide more details.

(2) A group at GSFC has had some success with microcalorimeters for 
solar use. Simon Bandler and Jay may have additional comments on this. 
The baseline detector would give ~2ev spectral resolution from 0.5-6kev, 
with a high resolution inner array of 32x32 pixels (~2"/pixel on a 
rocket) and a lower resolution outer array. The development work has 
proceeded to the point that we are likely to propose a solar rocket this 
year for the microcalorimeter.

Both of these operate in the soft wavelength band where we can more 
easily see coronal heating.

Ed

On 6/9/11 7:56 AM, Alan Gabriel wrote:
> 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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>
> -- 
> ______________________________________________________________________
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>
>
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