User:Tohline/Appendix/Ramblings/MyDoctoralStudents

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Chronology of Research Endeavors

Whitworth's (1981) Isothermal Free-Energy Surface
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Doctoral Students Tohline Has Advised

Doctoral Students Whom Tohline has Advised at LSU
Year of Ph.D. Student Name ED Jointly Advised? Quarter-Sized Mosaic Image
1988 Harold Williams    
1989 Dimitris M. Christodoulou    
1992 John Woodward    
1994 Horst Väth   w/ Detlev Koester (Univ. of Kiel, Germany)
1996 Kimberly C. (Barker) New    
1998 Paul Fisher    
1998 Saied Andalib    
1998 Erik Young   w/ Ganesh Chanmugam (LSU Physics & Astronomy)
1999 John E. Cazes    
1999 Howard S. Cohl    
2001 Eric I. Barnes    
2001 Patrick M. Motl <math>~\odot</math> w/ Juhan Frank (LSU Physics & Astronomy)
2004 Shangli Ou <math>~\odot</math>  
2006 Ravi Kumar Kopparapu <math>~\odot</math>  
2006 Richard P. Muffoletto <math>~\odot</math> w/ John Tyler (LSU Computer Science)
2010 Wes P. Even <math>~\odot</math>  
2010 Jay M. Call <math>~\odot</math>  
2011 Dominic C. Marcello <math>~\odot</math>  
2014 Zachary D. Byerly <math>~\odot</math>  

ED = Electronic Dissertation

Annotated

NOTE: In order to see a larger version of the primary image — or its annotated thumbnail companion, shown here, on the right — click once on the image, then click a second time on Full Resolution.

Outline of Research Activities

Years (approx.) Comments Significant Research Contributions Discussion
A CH V O
1976 - 1978

Tohline's dissertation research under the guidance of Peter Bodenheimer (UCSC) and David Black (NASA/Ames) was an early attempt to examine whether of not isothermal gas clouds whose mass exceeds the Jeans mass spontaneously fragment during a phase of free-fall collapse. The adopted Eulerian computational hydrodynamics scheme was first-order donor-cell based on the 2D (axisymmetric, cylindrical-coordinate) scheme described by Black & Bodenheimer (1976) but extended by Tohline to a 3D grid; a typical simulation was carried out on the CDC7600 at NASA/Ames and involved <math>~30^3 \approx 3 \times 10^4</math> grid cells. The self-consistently determined, time-dependent Newtonian gravitational potential was determined by combining (1) an FFT technique in the azimuthal coordinate direction, with (2) a Buneman Cyclic Reduction technique in R and Z.

Richard Durisen — a NASA/Ames postdoc at the time — said to me something along the lines of, "Hey! When you finish developing that hydrocode, let's get together and examine the dynamical stability of rapidly rotating, equilibrium configurations."

sf -- -- TBD
1978 - 1982

While at Yale University (1978 - 1980) and at Los Alamos National Laboratory (1980 - 1982), Tohline worked closely with Richard Durisen (Indiana University) to examine the onset and nonlinear development of nonaxisymmetric instabilities in differentially rotating, n = 3/2 polytropes whose internal angular momentum distribution was that of an n' = 0 sequence. Generally speaking, unstable eigenfrequencies matched earlier predictions (by other groups) based on linear stability analyses; unstable eigenfunctions displayed a two-armed spiral character. As the amplitude of unstable modes grew to nonlinear amplitude, the developed spiral arms were able to effectively redistribution angular momentum, preventing fragmentation/fission of the configurations.

Nelson Caldwell — a Yale graduate student at the time — showed Tohline some of his early work focused on the observationally determined properties of elliptical galaxies that display prominent dust lanes. Additional discussions led to a collaboration between Caldwell, Tohline, and Gregory Simonson — also a Yale graduate student at the time — in which the observed orientation of dust lanes can be explained in terms of dissipative settling of gas disks and, as a consequence, can be used to deduce the underlying geometry (e.g., oblate or prolate spheroidal) of each galaxy's mass distribution. With guidance from Tohline, Simonson completed a Yale University doctoral dissertation in which this settling model was extended to the context of polar rings in spiral galaxies.

When Tohline presented a seminar in the Department of Astronomy at Indiana University on the topic of "dust lanes in elliptical galaxies," Durisen asked what would happen to a settling gas disk if the underlying galaxy mass distribution was tumbling end over end — e.g., a cigar spinning about its shortest axis. The ensuing discussions led to a fruitful collaboration between Durisen and Tohline in which it became clear that steady-state warped disks could result. (After Tohline moved to LSU, extensions of this research work resulted in collaborative publications with several LSU graduate students — D. Christodoulou, K. New, H. Väth — and in Paul Fisher's doctoral dissertation research project.)

sf, gd -- -- -- TBD
Research areas in which significant contributions were made: Astrophysics (A), Computational Hydrodynamics (CH), Visualization (V), and Other (O). Subcategories under Astrophysics are sf (star formation), gd (galaxy dynamics), GR (sources of gravitational radiation).


Whitworth's (1981) Isothermal Free-Energy Surface

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Recommended citation:   Tohline, Joel E. (2021), The Structure, Stability, & Dynamics of Self-Gravitating Fluids, a (MediaWiki-based) Vistrails.org publication, https://www.vistrails.org/index.php/User:Tohline/citation