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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Scott,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'> I fully agree with most of what you
say. We need to be very cautious. The whole point of the paper (and
Phil’s) is to show that various uncertainties limit what you can infer
about the thermal properties of an observed plasma. We propose a simple method
to set approximate bounds on the range of valid interpretations. I
disagree with what you seemed to say about not being able to do much with
DEM/EM. We can learn a great deal about the physics of the corona and transition
region if we know the thermal distribution of the plasma. The key
question is whether we can determine DEM/EM reliably from observations. You
make an excellent point that all of the “inversion” methods,
including ours, assume ionization equilibrium. There are many situations where
this is not valid (e.g., early in a nanoflare event). Expect to see more
on this in the near future….<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Thanks for your comments,<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Jim<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> loops-bounces@solar.physics.montana.edu
[mailto:loops-bounces@solar.physics.montana.edu] <b>On Behalf Of </b>Scott W.
McIntosh<br>
<b>Sent:</b> Thursday, September 23, 2010 8:54 PM<br>
<b>To:</b> A mailing list for scientists involved in the observation and
modeling of solar loop structures<br>
<b>Subject:</b> Re: [Loops] EM loci<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Can I point out a paper to the list: <o:p></o:p></p>
<div>
<p class=MsoNormal><o:p> </o:p></p>
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<div>
<p class=MsoNormal><a href="http://adsabs.harvard.edu/abs/2010ApJ...708.1238J">http://adsabs.harvard.edu/abs/2010ApJ...708.1238J</a><o:p></o:p></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal>This paper encapsulates the problem in a concise form. I
could point out a couple more, but those are nearly 10 years old now, wow how
time flies. I have drawn my line in the sand with emission measures as a
practical diagnostic - once we have a DEM/EM, etc what can we do with it? As
far as I can tell there are only a few papers in the literature that deal with
that particular issue in a real sense and those are from further back in the
80s [look for papers by Carole Jordan].<o:p></o:p></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal>I am all for learning something about the solar plasma from
a zeroth order approach. However, no EM/DEM/Line Ratio estimation deals
with the real time-varying corona (or outer solar atmosphere as we need to deal
with a intrinsically coupled system). By definition, these diagnostic deal
with equilibrium processes and thermal populations - I am not entirely sure
that we have that in place and if we do is, is that the process doing the
"heavy lifting" or just the after effect procing the apparent
stationary state.....there is strong evidence of non-thermal processes
affecting the chromospheric, TR and coronal plasmas in the very same spectra
from which such diagnostics are derived [probably even worse for broadband EUV
imagers].<o:p></o:p></p>
</div>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal>Sorry, to be a bummer!<o:p></o:p></p>
</div>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal>-S. <o:p></o:p></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'>**---------------------------------------------------------------------------------------------**<o:p></o:p></span></p>
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<div>
<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'>
<span class=apple-tab-span> </span>Dr.
Scott W. McIntosh<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'><o:p> </o:p></span></p>
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<div>
<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'>National Center for Atmospheric Research
Phone: 303 497 1544 <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'> (Room 3624) High Altitude Observatory
<span class=apple-converted-space> </span>Fax:
303 497 1589<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'> 3080 Center Green Drive - CG1
<span class=apple-converted-space> </span><span
class=apple-tab-span> </span>
email: <a href="mailto:mscott@ucar.edu">mscott@ucar.edu</a><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'> <span
class=apple-converted-space> </span><span class=apple-tab-span> </span>Boulder,
CO 80301 <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'> <span
class=apple-converted-space> </span><span class=apple-tab-span> </span><a
href="http://people.hao.ucar.edu/mscott/">http://people.hao.ucar.edu/mscott/</a><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'><o:p> </o:p></span></p>
</div>
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<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'><o:p> </o:p></span></p>
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<p class=MsoNormal><span style='font-size:6.0pt;font-family:"Helvetica","sans-serif";
color:black'><o:p> </o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:6.0pt'><o:p> </o:p></span></p>
</div>
<p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<div>
<p class=MsoNormal>On Sep 23, 2010, at 7:25 AM, Klimchuk, James A. (GSFC-6710)
wrote:<o:p></o:p></p>
</div>
<p class=MsoNormal><br>
<br>
<o:p></o:p></p>
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<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Friends,<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>
The EM loci technique is frequently used to access whether a plasma is
isothermal. The attached paper addresses the uncertainty in this
technique and proposes a way to determine the range of thermal distribution
widths that are consistent with a set of emission line data.<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Cheers,<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>Jim<o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>********************************************************************************</span><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>James
A. Klimchuk</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>NASA
Goddard Space Flight Center</span><span style='font-size:11.0pt;font-family:
"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Solar
Physics Lab, Code 671</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Bldg.
21, Rm. 158</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Greenbelt,
MD 20771</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>USA</span><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Phone:
1-301-286-9060</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Fax:
1-301-286-7194</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>E-mail: <a
href="mailto:James.A.Klimchuk@nasa.gov">James.A.Klimchuk@nasa.gov</a></span><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Home
page: </span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><a
href="http://science.gsfc.nasa.gov/671/staff/bios/cs/James_Klimchuk_ssi.html">http://science.gsfc.nasa.gov/671/staff/bios/cs/James_Klimchuk_ssi.html</a><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>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).</span><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> </span><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>********************************************************************************</span><span
style='font-size:11.0pt;font-family:"Calibri","sans-serif"'><o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> <o:p></o:p></span></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> <o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:13.5pt;font-family:"Helvetica","sans-serif"'><em_loci.pdf>_______________________________________________<br>
Loops mailing list<br>
<a href="mailto:Loops@solar.physics.montana.edu">Loops@solar.physics.montana.edu</a><br>
<a href="https://mithra.physics.montana.edu/mailman/listinfo/loops">https://mithra.physics.montana.edu/mailman/listinfo/loops</a><o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
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