[Loops] EIS DEM for September 24-29 2010

[Bradshaw, Stephen James. (GSFC)[GEORGE MASON UNIVERSITY]]

Further to Jim's email (below) and his comment concerning the importance of non-equilibrium ionisation states during the early stages of nanoflare-type heating; anyone wishing to examine its likely importance (or otherwise) to their own investigations are welcome to use a code I have recently developed for exactly this purpose. Full details are provided in:

Bradshaw, S.J., 2009, A&A (Suppl. Ser.), 502, 409 (http://adsabs.harvard.edu/abs/2009A%26A...502..409B).

Briefly: the user supplies tabulated electron temperature and density values as a function of time (could be from analytical / numerical models or observations) and the solver will return the evolution of the ionisation state for the element(s) of choice. It will run in just a few seconds on a standard desktop PC and the output can then be used to calculate quantities such as emission line intensities.

Just drop me an email if you would like a copy of the code.

Best wishes,

Steve


Dr Stephen J. Bradshaw

NASA Goddard Space Flight Center,
Solar Physics Lab., Code 671,
Greenbelt,
MD 20771,
USA.

Tel: 1-301-286-9682

Email: stephen.bradshaw at nasa.gov


-----Original Message-----
From: loops-bounces at solar.physics.montana.edu [mailto:loops-bounces at solar.physics.montana.edu] On Behalf Of Klimchuk, James A. (GSFC-6710)
Sent: Friday, January 08, 2010 2:48 PM
To: A mailing list for scientists involved in the observation and modeling of solar loop structures
Subject: Re: [Loops] EIS DEM for September 24-29 2010

Hi all.  I have a quick comment about DEMs because I worry that some of the earlier e-mails may have left a wrong impression.  I've taken a look at Helen's DEM curves, and they are very much consistent with nanoflare heating.  The DEM at logT = 6.7 is what many of the models predict.  This does not prove nanoflare heating, but rather leaves it open as a possibility.  Helen's much reduced DEM at logT = 7.1 suggests that the nanoflares cannot be exceptionally strong.  I would caution, however, that ionization nonequilibrium effects are expected to be very important in the early stages of an event, and the true DEM may be much larger than what the observations suggest (as demonstrated by Steve and Fabio).  I also want to give credit to Brendan O'Dwyer, Helen's student who is the lead author on the paper with these results.

Happy, healthy, and productive 2010 to all!
Jim