Hi Loopsters,
We enjoyed a very successful workshop in Mallorca. Many thanks to the SOC and LOC and especially to their chairs, Inaki Ugarte Urra and Jose Luis Ballester, respectively. These guys put in a lot of hard work.
We also thank Spiro Antiochos, Joan Schmelz, and Robert Walsh, whose terms on the Steering Committee are ending. Please send me nominations for their replacements, including self nominations. The Steering Committee will then vote from a list of candidates. (Spiro, Joan, and Robert are eligible to serve again.)
It's never too early to start planning for the next workshop, in 2 years. Please contact me if you are interested in hosting. We have some tentative offers already, but they are highly tentative at this time.
Best wishes,
Jim
********************************************************************************
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(a)nasa.gov<mailto:James.A.Klimchuk@nasa.gov>
Home page: http://science.gsfc.nasa.gov/671/staff/bios/cs/James_Klimchuk_ssi.html
No endorsement by NASA is implied for any correspondence related to my role as an officer of professional organizations (American Geophysical Union, American Astronomical Society, International Astronomical Union).
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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,
Lisa Rightmire's MS thesis paper on EIS & XRT observations of a warm active region loop has been accepted for publication in ApJ. Please click here for a copy:
https://umdrive.memphis.edu/jschmelz/public/Loops/RightmireThesisPaper.pdf
Warm and Fuzzy: Temperature and Density Analysis of an Fe XV EIS Loop
Abstract: The Hinode EUV Imaging Spectrometer (EIS) and X-Ray Telescope (XRT) were designed in part to work together. They have the same spatial resolution and cover different but overlapping coronal temperature ranges. These properties make a combined data set ideal for multithermal analysis, where EIS provides the best information on the cooler corona (Log T $<$ 6.5) and XRT provides the best information on the hotter corona (Log T $>$ 6.5). Here, we analyze a warm non-flaring loop detected in images made in a strong EIS Fe XV emission line with a wavelength of 284.16 \AA\ and peak formation temperature of Log T $=$ 6.3. We perform Differential Emission Measure (DEM) analysis in three pixels at different heights above the footpoint and find multithermal results with the bulk of the emission measure in the range 6.0 $<$ Log T $<$ 6.6. Analysis with the EIS lines alone gave a DEM with huge amounts of emission measure at very high temperatures (Log T $>$7.2); analysis with XRT data alone resulted in a DEM that was missing most of the cooler emission measure required to produce many of the EIS lines. Thus both results were misleading and unphysical. It was only by combining the EIS and XRT data that we were able to produce a reasonable result, one without ad hoc assumptions on the shape and range of the DEM itself.
Regards,
Joan
Dear Loops Group,
It was a pleasure to see so many of you in Mallorca!
One of the papers I talked about has just been accepted for publication in ApJ:
Isothermal and Multithermal Analysis of Coronal Loops Observed with AIA: II. 211 A Selected Loops
Abstract: An important component of coronal loop analysis involves conflicting results on the cross-field temperature distribution. Are loops isothermal or multithermal? The Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory was designed in part to answer this question. AIA has a series of coronal filters that peak at different temperatures and cover the entire active region temperature range. These properties should make AIA ideal for multithermal analysis, but recent results have shown that the response functions of two of the filters, AIA 94 and 131 \AA, are missing a significant number of low-temperature emission lines. Here we analyze coronal loops from several active regions that were chosen in the 211 \AA\ channel of AIA, which has a peak response temperature of log T $=$ 6.3. The Differential Emission Measure (DEM) analysis of the 12 loops in our sample reveals that using data from the 131 \AA\ AIA filter distorts the results, and we have no choice but to do the analysis without these data. The 94 \AA\ data do not appear to be as important, simply because the chosen loops are not visible in this channel. If we eliminate the 131 \AA\ data, however, we find that our DEM analysis is not well-constrained on the cool temperature end of six of our loops. The information revealed by our 211-selected loops indicates that additional atomic data is required in order to pin down the cross-field temperature distribution.
Copies are available here:
https://umdrive.memphis.edu/jschmelz/public/Loops/AIA2_SchmelzEtAl.pdf
Regards,
Joan
Talks from Coronal Loops V Workshop can be found at
http://web.me.com/inigo.arregui/Iñigo_Arregui/LOOPS-talks.html
Regards. JLBallester
Dr. J. L. Ballester
Departament de Física
Universitat Illes Balears
E-07122 Palma de Mallorca (Spain)
phone: 34 971 173228
Fax: 34 971 173426
joseluis.ballester(a)uib.es
dfsjlb0(a)uib.es
jlballester(a)me.com
The list of participants in Coronal Loops V has been updated in the website: www.loops2011.org. Also, the pictures of the meeting can be found at http://gallery.me.com/inigo.arregui/100490.
Dr. J. L. Ballester
Departament de Física
Universitat Illes Balears
E-07122 Palma de Mallorca (Spain)
phone: 34 971 173228
Fax: 34 971 173426
joseluis.ballester(a)uib.es
dfsjlb0(a)uib.es
jlballester(a)me.com