[Loops] chromospheric nanoflares as the source of coronal plasma

[Klimchuk, James A. (GSFC-6710)]

Thanks, Piet.

Jim

> -----Original Message-----
> From: Loops [mailto:loops-bounces at solar.physics.montana.edu] On Behalf Of
> Petrus Martens
> Sent: Thursday, May 08, 2014 9:41 AM
> To: A mailing list for scientists involved in the observation and modeling of solar loop
> structures
> Subject: Re: [Loops] chromospheric nanoflares as the source of coronal plasma
> 
> 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:
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> >
> > No endorsement by NASA is implied for any correspondence related to my
> > official role in professional organizations.
> >
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> >
> >
> >
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