Dear coronal loopers,
I'm pleased to share a preprint on loop oscillations observed with AIA
that has been accepted for publication in ApJ.
Share and enjoy,
Cheers,
Markus
Aschwanden,M.J. and Schrijver,C.J. 2011, The Astrophysical Journal, ... (in press)
URL1="http://www.lmsal.com/~aschwand/eprints/2011_aia_osc.pdf" - _movies/"
Coronal loop oscillations observed with AIA : Kink-mode with cross-sectional and density oscillation
_______________________________________
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(a)lmsal.com
_______________________________________
Dear colleagues
please find at the following link the preprint of a work accepted
for publication on the ApJ Letters, showing new strong evidence of
finely-structured loops with impulsive nanoflare activity in active regions:
http://arxiv.org/abs/1106.1591
The abstract is below.
Best regards
Fabio Reale
Solar Dynamics Observatory discovers thin high temperature strands in
coronal active regions
Authors: Fabio Reale, Massimiliano Guarrasi, Paola Testa, Edward E.
DeLuca, Giovanni
Peres, Leon Golub
<http://arxiv.org/find/astro-ph/1/au:+Golub_L/0/1/0/all/0/1>
Abstract: One scenario proposed to explain the million degrees solar
corona is a finely-stranded corona where each strand is heated by a
rapid pulse. However, such fine structure has neither been resolved
through direct imaging observations nor conclusively shown through
indirect observations of extended superhot plasma. Recently it has
been shown that the observed difference in appearance of cool and
warm coronal loops (~1 MK, ~2-3 MK, respectively) -- warm loops
appearing "fuzzier" than cool loops -- can be explained by models of
loops composed of subarcsecond strands, which are impulsively heated
up to ~10 MK. That work predicts that images of hot coronal loops
(>~6 MK) should again show fine structure. Here we show that the
predicted effect is indeed widely observed in an active region with
the Solar Dynamics Observatory, thus supporting a scenario where
impulsive heating of fine loop strands plays an important role in
powering the active corona.
Dear Colleagues,
Our paper 'Patterns of Nanoflare Storm Heating Exhibited by an Active Region Observed with SDO/AIA' was recently accepted for publication in ApJ.
Please find the paper at:
http://arxiv.org/abs/1106.4196
Authors: Nicholeen Viall and James Klimchuk
Abstract:
It is largely agreed that many coronal loops---those observed at a temperature of about 1 MK--- are bundles of unresolved strands that are heated by storms of impulsive nanoflares. The nature of coronal heating in hotter loops and in the very important but largely ignored diffuse component of active regions is much less clear. Are these regions also heated impulsively, or is the heating quasi steady? The spectacular new data from the Atmospheric Imaging Assembly (AIA) telescopes on the Solar Dynamics Observatory (SDO) offer an excellent opportunity to address this question. We analyze the light curves of coronal loops and the diffuse corona in 6 different AIA channels and compare them with the predicted light curves from theoretical models. Light curves in the different AIA channels reach their peak intensities with predictable orderings as a function the nanoflare storm properties. We show that while some sets of light curves exhibit clear evidence of cooling after nanoflare storms, other cases are less straightforward to interpret. Complications arise because of line-of-sight integration through many different structures, the broadband nature of the AIA channels, and because physical properties can change substantially depending on the magnitude of the energy release. Nevertheless, the light curves exhibit predictable and understandable patterns consistent with impulsive nanoflare heating.
Cheers,
Nicki
************************
Nicholeen Viall
Code 671
NASA/Goddard Space Flight Center
Greenbelt, MD 20771
Email: Nicholeen.M.Viall(a)nasa.gov<mailto:Nicholeen.M.Viall@nasa.gov%3cmailto:Nicholeen.M.Viall@nasa.gov>
Phone: 301-286-4054