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==Suggested Doctoral Dissertation-Level Research Projects==
Over the years &#8212; dating back to my time as a J. Willard Gibbs Instructor at Yale University (1978 - 1980) and throughout my academic career at LSU (see [[Appendix/Ramblings/MyDoctoralStudents#Doctoral_Students_Tohline_Has_Advised|an accompanying list]]) &#8212;  I have helped more than twenty physics and/or astronomy graduate students identify a suitable topic for their doctoral dissertation research.  Although, in retirement, I am no longer formally advising doctoral students, I continue to recognize dissertation-level research projects that are ripe for investigation.  Here are brief descriptions of a number of such projects.  As time goes along, I expect to add chapters to my [[Main_Page|online H_Book]] that will supply each of these projects with a more substantive background foundation.  I would be happy to hand each of these projects off to an appropriately qualified graduate student who expresses sufficient interest in tackling the project in depth.

===Constructing Compressible Analogs of Riemann Ellipsoids===
We have known, for well over 100 years, that rapidly rotating, ellipsoidal-shaped equilibrium configurations can be constructed with a variety of different internal fluid velocity profiles &#8212; giving rise to Jacobi, Dedekind, or Riemann ellipsoids &#8212; ''if the fluid configuration has uniform density and is incompressible.''  [http://adsabs.harvard.edu/abs/2000ApJ...532.1051C Computational fluid-dynamic (CFD) simulations have demonstrated] that dynamically stable compressible analogs of Riemann ellipsoids can be constructed, under certain conditions.  The objective here is to develop a numerical technique, akin to the [http://www.phys.lsu.edu/astro/H_Book.current/Applications/Structure/HSCF_Code/HSCF.html Hachisu self-consistent field (HSCF) technique], by which a wide range of such equilibrium configurations  can be constructed ''a priori'', without relying on CFD techniques.
* [http://adsabs.harvard.edu/abs/2006ApJ...639..549O Shangli Ou] developed an HSCF-type technique that successfully constructs ''approximate'' equilibrium configurations that are analogs of Riemann ellipsoids
* [[Apps/RiemannEllipsoidsCompressible|Some thoughts regarding]] how a more satisfactory velocity flow-field might be incorporated into Ou's technique in order to achieve this project objective 
* Apart from my astronomy colleagues at LSU, I have had especially useful discussions of this project with Eric Hirschmann (BYU), David Neilsen (BYU), [https://www.semanticscholar.org/paper/A-hybrid-variational-level-set-approach-to-handle-Walker/7ee624ab9ffe45241cb0e5a0ce0898a6da201e7b Shawn W. Walker (2007)] (LSU Mathematics &amp; CCT), and Ricardo H. Nochetto (U. Maryland, Mathematics)
* Relevant to &hellip;

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<td width="4%" align="left">&nbsp;&nbsp;&nbsp;</td>
<td align="left">[http://www.phys.lsu.edu/astro/movie_captions/fission.html The fission hypothesis for binary star formation]</td>
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<td width="4%" align="left">&nbsp;&nbsp;&nbsp;</td>
<td align="left">[http://www.phys.lsu.edu/~tohline/fission.movies.html Fission-related CFD simulations conducted at LSU]</td>
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<td width="4%" align="left">&nbsp;&nbsp;&nbsp;</td>
<td align="left">[[ThreeDimensionalConfigurations/BinaryFission#Fission_Hypothesis_of_Binary_Star_Formation|Fission of liquid drops in spacelab experiments]]</td>
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<td width="4%" align="left">&nbsp;&nbsp;&nbsp;</td>
<td align="left">[http://www.phys.lsu.edu/astro/nap98/bf.final.html The Formation of Common-Envelope, Pre-Main-Sequence Binary Stars]</td>
</tr>
</table>

===Globular Cluster Formation During Galaxy-Galaxy Collisions===

The manuscript presented immediately below presents an hypothesis regarding globular cluster formation that came to me as a EUREKA! moment one day (in the mid-to-late 1990s) while I was attending a Physics &amp; Astronomy departmental colloquium at LSU.  The colloquium speaker was, as I recall, someone from U. C. Berkeley with experimental space sciences expertise; and the topic of the colloquium was Galactic cosmic rays &hellip; [[DissertationTopics/GCFormation|<more>]]  

As a matter of course during his presentation, the colloquium speaker reminded the audience &#8212; and me, in particular &#8212; that, in our Galaxy, the dense, cold "protostellar" cores of molecular clouds are coupled to the interstellar magnetic field (only) because the gas is partially ionized by Galactic cosmic rays.  Furthermore, the Galaxy's charged-particle cosmic-ray flux is highest near the mid-plane of the Galaxy's disk because the cosmic rays are trapped by the disk's relatively ordered, large-scale interstellar magnetic field.  All of a sudden, it occurred to me that, if our Galaxy were to collide with another galaxy &hellip; 
* Its disk and, along with it, the interstellar magnetic field would very likely become much less organized;
* Cosmic rays would no longer be well confined to the disk and  &#8212; as a consequence of streaming out of the disk at relativistic speeds &#8212; the flux of cosmic rays would fairly rapidly drop within the Galaxy's molecular clouds;
* The dense, protostellar cores of molecular clouds would fairly rapidly decouple from the magnetic field because the cores would no longer be sufficiently ionized.
EUREKA!  This would create an environment highly conducive to rapid star formation, perhaps throughout an entire giant molecular cloud (GMC) complex.  This would trigger a rapid burst of star formation and, perhaps, a transformation of the GMC into a massive, ''bound'' star cluster.  It is this idea and accompanying reasoning that is fleshed out in the paper that I wrote in 2000 (while on sabbatical leave at Caltech) in collaboration with Nick Scoville and Andrew Strong:

* Original manuscript (submitted to ''The Astrophysical Journal'' in June, 2000): [http://www.vistrails.org/images/Ms_globularClusters.pdf J. E. Tohline, N. Z. Scoville, &amp; A. W. Strong (2000)]

This paper was never published because the journal referee (see [[DissertationTopics/GCFormation#RefereeReport|accompanying material]]) requested a more extensive demonstration of the proposed model's viability, which I considered to be well beyond the scope and essential purpose of this paper.  I remain firmly convinced that the idea has a great deal of merit.  I offer this original manuscript as a foundation on which an appropriately qualified graduate student might build a more extensive demonstration of the viability of this proposed mechanism for globular cluster formation.