[Loops] More Hinode AR loops - Ugarte-Urra et al. 2009, ApJ

[Ignacio Ugarte Urra]

Hi all,

Just wanted to let you know about a paper on EIS/XRT observations of
coronal loops just accepted by ApJ.

http://arxiv.org/abs/0901.1075

Title: "Active region transition region loop populations and their
relationship to the corona"
Authors: Ignacio Ugarte-Urra, Harry P. Warren and David H. Brooks

Abstract:
The relationships among coronal loop structures at different
temperatures is not settled. Previous studies have suggested that
coronal loops in the core of an active region are not seen cooling
through lower temperatures and therefore are steadily heated. If loops
were cooling, the transition region would be an ideal temperature regime
to look for a signature of their evolution. The Extreme-ultraviolet
Imaging Spectrometer (EIS) on Hinode provides monochromatic images of
the solar transition region and corona at an unprecedented cadence and
spatial resolution, making it an ideal instrument to shed light on this
issue. Analysis of observations of active region 10978 taken in 2007
December 8 -- 19 indicates that there are two dominant loop populations
in the active region: core multi-temperature loops that undergo a
continuous process of heating and cooling in the full observed
temperature range 0.4-2.5 MK and even higher as shown by the X-Ray
Telescope (XRT); and peripheral loops which evolve mostly in the
temperature range 0.4-1.3 MK. Loops at transition region temperatures
can reach heights of 150 Mm in the corona above the limb and develop
downflows with velocities in the range of 39-105 km/s.

Best,
Ignacio
-- 
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 ~ Ignacio Ugarte-Urra ~
   Naval Research Laboratory. Code 7673U.                      
   4555 Overlook Ave SW. Washington, DC 20375
   Contractor. Spain.
   phone: (+1) 202 404 1779
   email: iugarte at ssd5.nrl.navy.mil
   http:  http://tcrb.nrl.navy.mil/~iuu
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