[Loops] summaries on nanoflare debates in "coronal loop workshops"

[Harry Warren]

Markus et al.,

It is unambiguous that there is a lot of dynamic activity going on in the
transition region. However:

. . . a significant fraction of the Sun's magnetic flux closes at low
heights (several Mm), so it is unclear how much of this activity is related
to what we see in the corona. 

. . . my impression of SOT magnetic field measurements is that active region
plage (where many active region loops are rooted) is unipolar. It is hard to
see how small-scale reconnection in the transition region could be important
here. I could be wrong about this! I'm sure that an SOT person could provide
a more definitive answer.

Best wishes,

Harry

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From: loops-bounces at mithra.physics.montana.edu
[mailto:loops-bounces at mithra.physics.montana.edu] On Behalf Of Markus J.
Aschwanden
Sent: Thursday, March 05, 2009 10:16 AM
To: Hugh Hudson; A mailing list for scientists involved in the observation
and modeling of solar loop structures
Subject: [Loops] summaries on nanoflare debates in "coronal loop workshops"

Dear Hugh,

Jim Klimchuk sent a great summary of the current status of a nanoflare model
around,
so it deals with all the PROs. An outside reader who wants to hear both
sides might be
interested to hear also the CONs, which you could find in the ApJ Letter
entitled
"An observational test that disproves coronal nanoflare heating models"
(Aschwanden
2008, ApJ 672, L135). The arguments made therein do not dismiss nanoflares
altogether, but come to the conclusion that they occur in the transition
region,
rather than in the corona (as Parker originally suggested).

Cheers,
Markus


On Mar 3, 2009, at 7:32 AM, Klimchuk, James A. (GSFC-6710) wrote:


Dear loops friends,
 
     Here is a paper I wrote for the Hinode II conference proceedings.  In
it, I try to do three things:  (1) review the arguments leading to the
conclusion that warm EUV loops must by bundles of strands heated by storms
of nanoflares (the flow chart some of you have asked about); (2) reconcile
the isothermal/multi-thermal debate in terms of the duration of the
nanoflare storm; and (3) address the possibility that loops can be explained
by thermal nonequilibrium.  Comments are welcomed.
 
Thanks,
James A. Klimchuk

____________________________________________
Dr. Markus J. Aschwanden
Solar & Astrophysics Laboratory
Lockheed Martin Advanced Techology Center
Org. ADBS, Bldg. 252
3251 Hanover St., Palo Alto, CA 94304, USA
Phone: 650-424-4001, FAX: 650-424-3994
URL: http://www.lmsal.com/~aschwand/
e-mail: aschwanden at lmsal.com
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