[Loops] chromospheric nanoflares as the source of coronal plasma

[Petrus Martens]

Nice work!

Piet


On 5/8/14 7:24 AM, Klimchuk, James A. (GSFC-6710) wrote:
> Dear friends,
>
>      You might be interested in a paper that Steve and I just submitted
> on "Chromospheric Nanoflares as the Source of Coronal Plasma." It can be
> downloaded at http://arxiv.org/abs/1405.1708. The abstract is below.
>
> Cheers,
>
> Jim
>
> It has been suggested that the hot plasma of the solar corona comes
> primarily from impulsive heating events, or nanoflares, that occur in
> the lower atmosphere, either in the upper part of the ordinary
> chromosphere or at the tips of type II spicules. We test this idea with
> a series of hydrodynamic simulations. We find that synthetic Fe XII
> (195) and Fe XIV (274) line profiles generated from the simulations
> disagree dramatically with actual observations. The integrated line
> intensities are much too faint; the blue shifts are much too fast; the
> blue-red asymmetries are much too large; and the emission is confined to
> low altitudes. We conclude that chromospheric nanoflares are not a
> primary source of hot coronal plasma. Such events may play an important
> role in producing the chromosphere and powering its intense radiation,
> but they do not, in general, raise the temperature of the plasma to
> coronal values. Those cases where coronal temperatures are reached must
> be relatively uncommon. The observed profiles of Fe XII and Fe XIV come
> primarily from plasma that is heated in the corona itself, either by
> coronal nanoflares or a quasi-steady coronal heating process.
> Chromospheric nanoflares might play a role in generating waves that
> provide this coronal heating.
>
> ********************************************************************************
>
> James A. Klimchuk
>
> NASA Goddard Space Flight Center
>
> Solar Physics Lab, Code 671
>
> Bldg. 21, Rm. 158
>
> Greenbelt, MD  20771
>
> USA
>
> Phone:  1-301-286-9060
>
> Fax:      1-301-286-7194
>
> E-mail: James.A.Klimchuk at nasa.gov <mailto:James.A.Klimchuk at nasa.gov>
>
> Homepage:
> http://science.gsfc.nasa.gov/sed/index.cfm?fuseAction=people.jumpBio&&iPhonebookId=15844
>
> No endorsement by NASA is implied for any correspondence related to my
> official role in professional organizations.
>
> ********************************************************************************
>
>
>
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