Dear Colleagues,
The attached paper has finally come out in the latest issue of ApJ (691:503–515, 2009 January 20). It seems we've been working on this one for a very long time!
Regards, Joan
ARE CORONAL LOOPS ISOTHERMAL OR MULTITHERMAL? J.T. Schmelz, K. Nasraoui, L.A. Rightmire, J.A. Kimble, G. Del Zanna, J.W. Cirtain, E.E. DeLuca & H.E. Mason
ABSTRACT Surprisingly few solar coronal loops have been observed simultaneously with TRACE and SOHO/Coronal Diagnostics Spectrometer (CDS), and even fewer analyses of these loops have been conducted and published. The SOHO Joint Observing Program 146 was designed in part to provide the simultaneous observations required for in-depth temperature analysis of active region loops and determine whether these loops are isothermal or multithermal. The data analyzed in this paper were taken on 2003 January 17 of AR 10250. We used TRACE filter ratios, emission measure loci, and two methods of differential emission measure analysis to examine the temperature structure of three different loops. TRACE and CDS observations agree that Loop 1 is isothermal with log T = 5.85, both along the line of sight as well as along the length of the loop leg that is visible in the CDS field of view. Loop 2 is hotter than Loop 1. It is multithermal along the line of sight, with significant emission between 6.2 < log T < 6.4, but the loop apex region is out of the CDS field of view so it is not possible to determine the temperature distribution as a function of the loop height. Loop 3 also appears to be multithermal, but a blended loop that is just barely resolved with CDS may be adding cool emission to the Loop 3 intensities and complicating our results. So, are coronal loops isothermal or multithermal? The answer appears to be yes.
Link:
http://www.iop.org/EJ/article/0004-637X/691/1/503/apj_691_1_503.pdf?request-...
Dear Joan,
We have presented some MHD seismological evidence that the loops have fine multi-thermal structure:
\bibitem[King et al.(2003)]{2003A&A...404L...1K} King, D.~B., Nakariakov, V.~M., Deluca, E.~E., Golub, L., McClements, K.~G.\ 2003.\ Propagating EUV disturbances in the Solar corona: Two-wavelength observations.\ Astronomy and Astrophysics 404, L1-L4.
http://adsabs.harvard.edu/abs/2003A%26A...404L...1K
All the best,
Valery
-----Original Message----- From: loops-bounces@mithra.physics.montana.edu on behalf of Joan T Schmelz (jschmelz) Sent: Thu 1/15/2009 8:53 PM To: A mailing list for scientists involved in the observation andmodeling ofsolar loop structures Cc: kaouther2001@yahoo.com; Lisa Ann Rightmire(lrightmr); Jason Andrew Kimble (jakimble) Subject: Re: [Loops] New Loops Paper
Dear Colleagues,
The attached paper has finally come out in the latest issue of ApJ (691:503-515, 2009 January 20). It seems we've been working on this one for a very long time!
Regards, Joan
ARE CORONAL LOOPS ISOTHERMAL OR MULTITHERMAL? J.T. Schmelz, K. Nasraoui, L.A. Rightmire, J.A. Kimble, G. Del Zanna, J.W. Cirtain, E.E. DeLuca & H.E. Mason
ABSTRACT Surprisingly few solar coronal loops have been observed simultaneously with TRACE and SOHO/Coronal Diagnostics Spectrometer (CDS), and even fewer analyses of these loops have been conducted and published. The SOHO Joint Observing Program 146 was designed in part to provide the simultaneous observations required for in-depth temperature analysis of active region loops and determine whether these loops are isothermal or multithermal. The data analyzed in this paper were taken on 2003 January 17 of AR 10250. We used TRACE filter ratios, emission measure loci, and two methods of differential emission measure analysis to examine the temperature structure of three different loops. TRACE and CDS observations agree that Loop 1 is isothermal with log T = 5.85, both along the line of sight as well as along the length of the loop leg that is visible in the CDS field of view. Loop 2 is hotter than Loop 1. It is multithermal along the line of sight, with significant emission between 6.2 < log T < 6.4, but the loop apex region is out of the CDS field of view so it is not possible to determine the temperature distribution as a function of the loop height. Loop 3 also appears to be multithermal, but a blended loop that is just barely resolved with CDS may be adding cool emission to the Loop 3 intensities and complicating our results. So, are coronal loops isothermal or multithermal? The answer appears to be yes.
Link:
http://www.iop.org/EJ/article/0004-637X/691/1/503/apj_691_1_503.pdf?request-... _______________________________________________ Loops mailing list Loops@solar.physics.montana.edu https://mithra.physics.montana.edu/mailman/listinfo/loops
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