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<th nowrap="nowrap" valign="BASELINE" align="RIGHT">Subject:
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<td>Plasma Theory/Nonlinear Dynamics Seminar: "Symplectic
and Variational Integration" - John M. Finn</td>
</tr>
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<th nowrap="nowrap" valign="BASELINE" align="RIGHT">Date: </th>
<td>Thu, 5 Apr 2018 18:43:46 +0000</td>
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<th nowrap="nowrap" valign="BASELINE" align="RIGHT">From: </th>
<td>Wilkinson, Ellie V <a class="moz-txt-link-rfc2396E" href="mailto:evwilk@wm.edu"><evwilk@wm.edu></a></td>
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<th nowrap="nowrap" valign="BASELINE" align="RIGHT">To: </th>
<td><a class="moz-txt-link-abbreviated" href="mailto:physics2017@physics.wm.edu">physics2017@physics.wm.edu</a>
<a class="moz-txt-link-rfc2396E" href="mailto:physics2017@physics.wm.edu"><physics2017@physics.wm.edu></a></td>
</tr>
<tr>
<th nowrap="nowrap" valign="BASELINE" align="RIGHT">CC: </th>
<td><a class="moz-txt-link-abbreviated" href="mailto:undergrads2017@physics.wm.edu">undergrads2017@physics.wm.edu</a>
<a class="moz-txt-link-rfc2396E" href="mailto:undergrads2017@physics.wm.edu"><undergrads2017@physics.wm.edu></a></td>
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v:shapes="Picture_x0020_1" class="" align="left" hspace="12"
height="242" width="191"><!--[endif]--><b><u><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif;color:#00B050">Plasma Theory/Nonlinear
Dynamics Seminar</span></u></b><span
style="font-size:12.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif">Wednesday, April 11, 2018<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif">12:00 PM
<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif">Small Hall, Room 235<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif"> <o:p></o:p></span></p>
<p class="MsoNormal"><b><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif;color:#00B050">John M. Finn
</span></b><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif">[Host: E. Tracy]<b>
</b><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif">Tibbar Plasma Technologies; Los Alamos
National Laboratory (retired)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif"> Title of Talk: </span></b><b><span
style="font-size:14.0pt;font-family:"Times New
Roman",serif;color:#00B050">“Symplectic and
Variational Integration”</span></b><b><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif"><o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:12.0pt"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif"><br>
<br>
<br>
<b><span style="color:#00B050">Abstract:</span></b> In the
context of canonical Hamiltonian systems, variational
integrators provide an alternative way of deriving
symplectic integrators. Variational integrators can be
formed by discretizing the action based on a conventional
configuration space Lagrangian, or alternately based on
discretizing a phase space action principle. A phase space
action principle leads to an ODE system which is degenerate,
producing the first order canonical Hamiltonian equations of
motion. A haphazard discretization can lead to discrete
equations that are higher order in time, allowing for
parasitic modes, which can be unstable. More careful
discretizations can lead to a system which is properly
degenerate. I present a review of these concepts and extend
them to two noncanonical systems of interest in plasma
physics, namely magnetic field lines and the guiding center
equations of motion. A major outcome of this work is that
for the discrete system to be properly degenerate, there is
a straightforward test, based on the discrete form of the
Hessian.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif;color:#00B050">Speaker Bio:</span></b><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif;color:#00B050">
</span><span style="font-size:12.0pt;font-family:"Times
New Roman",serif">John M. Finn received his PhD from
the University of Maryland in 1974. He worked at the Naval
Research Laboratory, at the University of Maryland and,
since 1993, at Los ALamos National Laboratory. He retired
from LANL in 2016 to form the startup Tibbar Plasma
Technologies, Inc. His research has been in plasma physics,
for application to magnetic fusion as well as solar and
astrophysical problems, with a focus on the application of
Dynamical Systems to plasmas.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif"><br>
Everyone is invited.<o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Times New
Roman",serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span
style="font-size:10.0pt;font-family:"Times New
Roman",serif;color:black">******</span><span
style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><b><span
style="font-size:12.0pt;font-family:"Monotype
Corsiva";color:#1F497D">Eleonor V. Wilkinson</span></b><span
style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Georgia",serif;color:black">Administrative
& Office Specialist
</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Georgia",serif;color:black">The
College of William & Mary-Physics<br>
Small Hall, Room 123<br>
300 Ukrop Way<br>
Williamsburg, VA 23185</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Times New
Roman",serif;color:black">Telephone: 757-221-3503</span><span
style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span
style="font-size:9.0pt;font-family:"Times New
Roman",serif;color:black">Fax: 757-221-3540</span><span
style="color:black"><o:p></o:p></span></p>
<p class="MsoPlainText"> <o:p></o:p></p>
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