Hi everyone,
In the spirit of a number of recent papers that have been focused on trying
to determine the dominant components of the emission in the wavelength
channels of imaging instruments (AIA, in particular), Jim and I would like
to share with you all a link to a paper on this very topic that was recently
published in the ApJ Supplement Series:
http://iopscience.iop.org/0067-0049/194/2/26/pdf/apjs_194_2_26.pdf
Our aim in carrying out the work described in this paper was to provide a
large amount of quantitative data from our modeling studies that we hope
will be of use in the analysis of observationally gathered data.
Best wishes,
Steve
-----Original Message-----
From: loops-bounces(a)solar.physics.montana.edu
[mailto:loops-bounces@solar.physics.montana.edu] On Behalf Of Paola Testa
Sent: Tuesday, September 20, 2011 10:00 AM
To: A mailing list for scientists involved in the observation and modeling
of solar loop structures
Cc: Juan Martinez Sykora
Subject: [Loops] Forward modeling of emission in SDO/AIA passbands from
dynamic 3D simulations
Hello all,
here is a link to a preprint of a paper, accepted for publication on ApJ,
that is also discussing issues related to the interpretation of AIA
observations:
http://adsabs.harvard.edu/abs/2011arXiv1109.0704M
cheers,
Paola
On 9/9/11 12:03 PM, Giulio Del Zanna wrote:
>
> Dear colleagues,
>
> here is a link to a preprint that discusses various
> (important) issues related to the interpretation of AIA data:
>
> http://solar.physics.montana.edu/cgi-bin/eprint/index.pl?entry=15555
>
> Those of you that were present at the excellent Mallorca meeting might
> recall the issues we raised there. The paper, which follows on from
> O'Dwyer et al., contains more.
>
> I encourage all to follow the example in the Appendix to calculate
> your own AIA responses using CHIANTI. We will soon release v.7, but do
> not expect huge differences.
> We are working to try and improve the atomic data for AIA, more to come.
>
>
> best wishes,
_______________________________________________
Loops mailing list
Loops(a)solar.physics.montana.edu
https://mithra.physics.montana.edu/mailman/listinfo/loops
Dear friends,
You might be interested in my recent paper on "The Role of Type II Spicules in the Upper Solar Atmosphere," which can be downloaded at http://arxiv.org/abs/1207.7048
Cheers,
Jim
ABSTRACT:
We examine the suggestion that most of the hot plasma in the Sun's
corona comes from type II spicule material that is heated as it is
ejected from the chromosphere. This contrasts with the traditional
view that the corona is filled via chromospheric evaporation that
results from coronal heating. We explore the observational
consequences of a hypothetical spicule dominated corona and conclude
from the large discrepancy between predicted and actual observations
that only a small fraction of the hot plasma can be supplied by
spicules (<2% in active regions and <5% in the quiet Sun). The
red-blue asymmetries of EUV spectral lines and the ratio of lower
transition region (LTR; T<0.1 MK) to coronal emission measures
are both predicted to be 2 orders of magnitude larger than observed.
Furthermore, hot spicule material would cool dramatically by
adiabatic expansion as it rises into the corona, so coronal heating
would be required to maintain the high temperatures that are seen at
all altitudes. The necessity of coronal heating is inescapable.
Traditional coronal heating models predict far too little emission
from the LTR, and we suggest that this emission comes primarily from
the bulk of the spicule material that is heated to <0.1 MK and
is visible in He II (304 A) as it falls back to the surface.
********************************************************************************
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>
Homepage: https://sedupdate.gsfc.nasa.gov/sed/index.cfm?fuseAction=people.jumpBio&&iP…
No endorsement by NASA is implied for any correspondence related to my role as an officer of professional organizations (American Geophysical Union, International Astronomical Union, American Astronomical Society).
********************************************************************************
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).
********************************************************************************
Dear colleagues
please find at the following link the preprint of a work accepted
for publication in Astronomy & Astrophysics, showing the detection of a
minor but significant very hot (~ 7MK) component in quiescent active
regions, with the SphinX instrument on-board CORONAS-PHOTON:
http://arxiv.org/abs/1207.4665
This hot component is invariably present both at high and low emission
regimes, i.e. even excluding resolvable microflares.
The abstract is below.
Best regards
Fabio Reale
X-raying hot plasma in solar active regions with the SphinX spectrometer
M. Miceli, F. Reale, S. Gburek, S. Terzo, M. Barbera, A. Collura, J.
Sylwester, M. Kowalinski, P. Podgorski, M. Gryciuk
The detection of very hot plasma in the quiescent corona is important
for diagnosing heating mechanisms. The presence and the amount of such
hot plasma is currently debated. The SphinX instrument on-board
CORONAS-PHOTON mission is sensitive to X-ray emission well above 1 keV
and provides the opportunity to detect the hot plasma component. We
analyzed the X-ray spectra of the solar corona collected by the SphinX
spectrometer in May 2009 (when two active regions were present). We
modelled the spectrum extracted from the whole Sun over a time window of
17 days in the 1.34-7 keV energy band by adopting the latest release of
the APED database. The SphinX broadband spectrum cannot be modelled by a
single isothermal component of optically thin plasma and two components
are necessary. In particular, the high statistics and the accurate
calibration of the spectrometer allowed us to detect a very hot
component at ~7 million K with an emission measure of ~2.7 x 10^44
cm^-3. The X-ray emission from the hot plasma dominates the solar X-ray
spectrum above 4 keV. We checked that this hot component is invariably
present both at high and low emission regimes, i.e. even excluding
resolvable microflares. We also present and discuss a possible
non-thermal origin (compatible with a weak contribution from
thick-target bremsstrahlung) for this hard emission component. Our
results support the nanoflare scenario and might confirm that a minor
flaring activity is ever-present in the quiescent corona, as also
inferred for the coronae of other stars.
--
*****************************************************************************
Dr. Fabio Reale, Ph.D.
Professore Associato
Dipartimento di Fisica, Universita` di Palermo
P.za Parlamento 1, 90134 Palermo - ITALY
Tel: +39 091 233 237
Fax: +39 091 233 444
*****************************************************************************
I am pleased to announce that Susanna Parenti, Inaki Ugarte Urra, and Nicki Viall have been elected to the Coronal Loops Workshops Steering Committee to replace outgoing members Spiro Antiochos, Joan Schmelz, and Robert Walsh. In addition, Fabio Reale has been elected the new chair. The committee will now begin to evaluate the proposals we have received for hosting the summer 2013 workshop. Additional proposals are still welcomed.
Thanks,
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>
Homepage: https://sedupdate.gsfc.nasa.gov/sed/index.cfm?fuseAction=people.jumpBio&&iP…
No endorsement by NASA is implied for any correspondence related to my role as an officer of professional organizations (American Geophysical Union, International Astronomical Union, American Astronomical Society).
********************************************************************************