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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Hi Scott,<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><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> Tuesday, July 31, 2012 10:46 AM<br><b>To:</b> A mailing list for scientists involved in the observation andmodeling of solar loop structures<br><b>Cc:</b> (Loops@solar.physics.montana.edu)<br><b>Subject:</b> Re: [Loops] type II spicule paper<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Hi Jim, <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Just scanned through, will send you comments after a thorough reading, but looks like a fair discussion. Couple of points though:<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Are "A" waves a viable energetic supply to the corona? They get no mention and I understand that the net effect of their dissipation would be nanoflares-like heating distribution. <o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>*** In principle, Alfven waves could be heating the corona, at least in the quiet Sun, as your recent work suggests. And indeed, wave heating would likely fit into the classification of nanoflares, since there would be an impulsive energy release from the perspective of an individual magnetic flux strand. But my paper isn’t attempting to address the nature of coronal heating. It simply means to show that there must be an energy release in the corona in order to explain the hot plasma that we observe there. Ejecting hot material at the tips of spicules isn’t enough if you buy my analysis.<o:p></o:p></span></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Btw, in addition to the above, discriminatory studies of quiet and coronal hole plasmas hold the key to the down-up (evaporative) vs up-down (type 2 "initiated") mass components of the mass cycle. It is a real push to expect the original energy supply for them to be different, but in one the coronal backwash is missing. The (detailed) study of the multi-component line profiles between the two should show the relative weighting of evaporative processes (regardless of their origin - see above) in the QS. My student has done a pretty detailed study of this and is about to submit a paper on her results - I will distribute to the list once submitted.<o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>*** I look forward to the paper. Regarding multi-component line profiles (weakly red shifted line core with a blue wing component), I would make the following point. The core emission likely comes from hot material that is cooling and draining, regardless of whether the hot material came from evaporation or spicules. The blue wing emission that is seen in lines <2 MK likely comes from spicules. Coronal nanoflares (reconnection, waves, whatever) are expected to produce blue wing emission only in very hot (>3 MK) lines, at least according to the modeling work that Spiros and I did in 2006. So, my picture is that the corona is comprised of unresolved strands. Most are dominated by coronal heating and some are dominated by type II spicules.<o:p></o:p></span></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Last point: why can't type-Ii spicules be the manifestation of nanoflares in a stratified inhomogeneous plasma?<o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Depends on where the nanoflares occur. Nanoflares that occur in the transition region or corona (in plasma that is originally hotter than 10^4 K) will not produce ejections of cold material. I have a discussion of this in the paper. Nanoflares that occur deep in the chromosphere, below the eventual spicule, can produce cold ejections.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Thanks for the comments!<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Jim<o:p></o:p></span></p></div><div><p class=MsoNormal><br>Cheers, Scott<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Sent from my iPhone<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Dr. Scott W. McIntosh<o:p></o:p></p></div><div><p class=MsoNormal>High Altitude Observatory<o:p></o:p></p></div><div><p class=MsoNormal>NCAR/UCAR, Boulder CO<span class=apple-style-span> </span><o:p></o:p></p></div><div><p class=MsoNormal><span class=apple-style-span>off: (303) 497-1544</span><o:p></o:p></p></div><p class=MsoNormal><span class=apple-style-span>mob: (720) 340-6263</span><o:p></o:p></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><br>On Jul 31, 2012, at 7:47, "Klimchuk, James A. (GSFC-6710)" <<a href="mailto:james.a.klimchuk@nasa.gov">james.a.klimchuk@nasa.gov</a>> wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal>Dear friends,<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal> 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 <a href="http://arxiv.org/abs/1207.7048">http://arxiv.org/abs/1207.7048</a><o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>Cheers,<o:p></o:p></p><p class=MsoNormal>Jim<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal>ABSTRACT:<o:p></o:p></p><p class=MsoNormal>We examine the suggestion that most of the hot plasma in the Sun's <o:p></o:p></p><p class=MsoNormal>corona comes from type II spicule material that is heated as it is<o:p></o:p></p><p class=MsoNormal>ejected from the chromosphere. This contrasts with the traditional<o:p></o:p></p><p class=MsoNormal>view that the corona is filled via chromospheric evaporation that<o:p></o:p></p><p class=MsoNormal>results from coronal heating. We explore the observational<o:p></o:p></p><p class=MsoNormal>consequences of a hypothetical spicule dominated corona and conclude<o:p></o:p></p><p class=MsoNormal>from the large discrepancy between predicted and actual observations<o:p></o:p></p><p class=MsoNormal>that only a small fraction of the hot plasma can be supplied by<o:p></o:p></p><p class=MsoNormal>spicules (<2% in active regions and <5% in the quiet Sun). The<o:p></o:p></p><p class=MsoNormal>red-blue asymmetries of EUV spectral lines and the ratio of lower<o:p></o:p></p><p class=MsoNormal>transition region (LTR; T<0.1 MK) to coronal emission measures<o:p></o:p></p><p class=MsoNormal>are both predicted to be 2 orders of magnitude larger than observed. <o:p></o:p></p><p class=MsoNormal>Furthermore, hot spicule material would cool dramatically by<o:p></o:p></p><p class=MsoNormal>adiabatic expansion as it rises into the corona, so coronal heating<o:p></o:p></p><p class=MsoNormal>would be required to maintain the high temperatures that are seen at<o:p></o:p></p><p class=MsoNormal>all altitudes. The necessity of coronal heating is inescapable. <o:p></o:p></p><p class=MsoNormal>Traditional coronal heating models predict far too little emission<o:p></o:p></p><p class=MsoNormal>from the LTR, and we suggest that this emission comes primarily from<o:p></o:p></p><p class=MsoNormal>the bulk of the spicule material that is heated to <0.1 MK and<o:p></o:p></p><p class=MsoNormal>is visible in He II (304 A) as it falls back to the surface.<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>********************************************************************************</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>James A. Klimchuk</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>NASA Goddard Space Flight Center</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Solar Physics Lab, Code 671</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Bldg. 21, Rm. 158</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Greenbelt, MD 20771</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>USA</span><o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Phone: 1-301-286-9060</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Fax: 1-301-286-7194</span><o:p></o:p></p><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><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Homepage: </span><a href="https://sedupdate.gsfc.nasa.gov/sed/index.cfm?fuseAction=people.jumpBio&&iPhonebookId=15844">https://sedupdate.gsfc.nasa.gov/sed/index.cfm?fuseAction=people.jumpBio&&iPhonebookId=15844</a><o:p></o:p></p><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, International Astronomical Union, American Astronomical Society).</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>********************************************************************************</span><o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p></div></blockquote><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><p class=MsoNormal><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'>_______________________________________________<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></div></blockquote></div></div></body></html>