<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">My little nail for Jack Scudders velocity filtration coffin:<div><div><table style="font-family: Times; "><tbody><tr><td nowrap="" valign="top" align="left"><b>Title:</b></td><td><br></td><td align="left" valign="top">Kinetic electrons in high-speed solar wind streams: Formation of high-energy tails</td></tr><tr><td nowrap="" valign="top" align="left"><b>Authors:</b></td><td><br></td><td align="left" valign="top"><a href="http://adsabs.harvard.edu/cgi-bin/author_form?author=Lie-Svendsen&fullauthor=Lie-Svendsen,%20%c3%98ystein&charset=UTF-8&db_key=AST" style="color: rgb(0, 0, 255); ">Lie-Svendsen, Øystein</a>; <a href="http://adsabs.harvard.edu/cgi-bin/author_form?author=Hansteen,+V&fullauthor=Hansteen,%20Viggo%20H.&charset=UTF-8&db_key=AST" style="color: rgb(0, 0, 255); ">Hansteen, Viggo H.</a>; <a href="http://adsabs.harvard.edu/cgi-bin/author_form?author=Leer,+E&fullauthor=Leer,%20Egil&charset=UTF-8&db_key=AST" style="color: rgb(0, 0, 255); ">Leer, Egil</a></td></tr><tr><td nowrap="" valign="top" align="left"><b>Publication:</b></td><td><br></td><td align="left" valign="top">Journal of Geophysical Research, Volume 102, Issue A3, p. 4701-4718 (<a href="http://www.agu.org/journals/jgr" style="color: rgb(0, 0, 255); ">JGR Homepage</a>)</td></tr><tr><td nowrap="" valign="top" align="left"><b>Publication Date:</b></td><td><br></td><td align="left" valign="top">03/1997</td></tr><tr><td nowrap="" valign="top" align="left"><b>Origin:</b></td><td><br></td><td align="left" valign="top"><a href="http://www.agu.org/" style="color: rgb(0, 0, 255); ">AGU</a></td></tr><tr><td nowrap="" valign="top" align="left"><b>Keywords:</b></td><td><br></td><td align="left" valign="top">Interplanetary Physics: Solar wind plasma, Interplanetary Physics: Sources of the solar wind, Solar Physics, Astrophysics, and Astronomy: Corona, and Astronomy: Coronal holes</td></tr><tr><td nowrap="" valign="top" align="left"><b>DOI:</b></td><td><br></td><td align="left" valign="top"><a href="http://dx.doi.org/10.1029/96JA03632" style="color: rgb(0, 0, 255); ">10.1029/96JA03632</a></td></tr><tr><td nowrap="" valign="top" align="left"><b>Bibliographic Code:</b></td><td><br></td><td align="left" valign="top"><a href="http://adsabs.harvard.edu/abs/1997JGR...102.4701L" style="color: rgb(0, 0, 255); ">1997JGR...102.4701L</a></td></tr></tbody></table><h3 align="center" style="font-family: Times; ">Abstract</h3><span class="Apple-style-span" style="font-family: Times; ">We study the evolution of the electron velocity distribution function in high-speed solar wind streams from the collision-dominated corona and into the collisionless interplanetary space. The model we employ solves the kinetic transport equation with the Fokker-Planck collision operator to describe Coulomb collisions between electrons. We use a test particle approach, where test electrons are injected into a prescribed solar wind background. The density, temperature, and electric field associated with the background are computed from fluid models. The test electrons are in thermal equilibrium with the background at the base of the corona, and we study the evolution of the velocity distribution of the test electrons as a function of altitude. We find that velocity filtration, due to the energy dependence of the Coulomb cross section, is a small effect and is not capable of producing significant beams in the distribution or a temperature moment that increases with altitude. The distribution function is mainly determined by the electric field and the expanding geometry and consists of a population with an almost isotropic core which is bound in the electrostatic potential and a beam-like high-energy tail which escapes. The trapped electrons contribute significantly to the even moments of the distribution function but almost nothing to the odd moments; the drift speed and energy flux moments are carried solely by the tail. In order to describe the high-speed solar wind observed near 0.3 AU by the Helios spacecraft, we use a multifluid model where ions are heated preferentially. The resulting test electron distribution at 0.3 AU, in this background, is in very good agreement with the velocity distributions observed by the Helios spacecraft.</span></div><div><font class="Apple-style-span" face="Times"><br></font></div><div><font class="Apple-style-span" face="Times"><div style="font-family: Helvetica; ">1) Electron temperatures are low -> polarization electric field is weak, so no matter how you describe them the electrons don't contribute much to the SW heat flux.</div><div style="font-family: Helvetica; ">2) Observations at 0.3 AU can be reproduced without any Scudder magic.</div><div style="font-family: Helvetica; "><br></div><div style="font-family: Helvetica; ">Best wishes,</div><div style="font-family: Helvetica; ">Viggo<br></div><div><br></div></font></div><div><div><div>On Jul 31, 2012, at 18:42 , Charles C. Kankelborg wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div>So, Anderson concluded that the velocity filtration model needed to be redone with Coulomb collisions included. Dorelly and Scudder came back in 2003 with a paper concluding that "the electron heat flux is determined by the essentially collisionless high-energy tail" of the distribution:<br><br><a href="http://adsabs.harvard.edu/abs/2003JGRA..108.1294D">http://adsabs.harvard.edu/abs/2003JGRA..108.1294D</a><br><br>Does that mean the coulomb collisions don't really affect prediction of energy transport? I haven't followed the trail of citations any farther...<br><br>Charles<br><br><br>On 2012 Jul 31, , at 9:27 AM, Dana Longcope wrote:<br><br><blockquote type="cite">Stephen Anderson did a very thorough analysis of how Coulomb collisions affect the model.<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">http://adsabs.harvard.edu/abs/1994ApJ...437..860A<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">dana<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">-----------------------------------------------------------<br></blockquote><blockquote type="cite">Dana Longcope | Dept. of Physics<br></blockquote><blockquote type="cite"> Professor | Montana State University<br></blockquote><blockquote type="cite"> (406) 994-7851 | Bozeman, MT 59717<br></blockquote><blockquote type="cite"> dana@solar.physics.montana.edu<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">On Jul 31, 2012, at 9:20 AM, Petrus Martens wrote:<br></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><blockquote type="cite"> Do you mean velocity filtration, where the corona is simply particles from the<br></blockquote></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">tail of the chromospheric distribution function? That theory has been largely discredited.<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">That's news to me. Do you have a reference?<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Piet<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite"><martens.vcf>_______________________________________________<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Loops mailing list<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">Loops@solar.physics.montana.edu<br></blockquote></blockquote><blockquote type="cite"><blockquote type="cite">https://mithra.physics.montana.edu/mailman/listinfo/loops<br></blockquote></blockquote><blockquote type="cite"><br></blockquote><blockquote type="cite">_______________________________________________<br></blockquote><blockquote type="cite">Loops mailing list<br></blockquote><blockquote type="cite">Loops@solar.physics.montana.edu<br></blockquote><blockquote type="cite">https://mithra.physics.montana.edu/mailman/listinfo/loops<br></blockquote><br>________________________________________________________________________<br>Charles Kankelborg AC7NY |<br>260C EPS Building | "If Christ is risen, nothing else matters.<br>Physics Department | And if Christ is not risen --- nothing else<br>Montana State University | matters."<br>Bozeman, MT 59717 |<br>Phone: 406-994-7853 | --Jaroslav Pelikan<br>FAX: 406-994-4452 |<br>http://solar.physics.montana.edu/kankel/<br><br><br><br><br><br>_______________________________________________<br>Loops mailing list<br>Loops@solar.physics.montana.edu<br>https://mithra.physics.montana.edu/mailman/listinfo/loops<br></div></blockquote></div><br><div apple-content-edited="true">
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">========================================================</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">Viggo H. Hansteen <a href="http://www.astro.uio.no/~viggoh">http://www.astro.uio.no/~viggoh</a></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">Institutt for teoretisk astrofysikk tel: +47-22856120</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">PB 1029, Blindern fax: +47-22856505</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">N-0315 Oslo, Norway <a href="mailto:Viggo.Hansteen@astro.uio.no">Viggo.Hansteen@astro.uio.no</a></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" style="font: normal normal normal 12px/normal Helvetica; ">========================================================</font></div></div></span>
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