# Robert Dewar

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## About

**CURRICULUM VITAE** **Emeritus Professor Robert Leith DEWAR, FAA**

**Date and Place of Birth: **March 1, 1944, Melbourne

**Academic Qualifications:**

BSc (1964), MSc (1967), University of Melbourne.

PhD (1970) Princeton University.

**Honours:**

Centenary Medal, 2003.

Elected Fellow of the Australian Academy of Science, 1992.

Elected Fellow of the American Physical Society, 1980.

**Membership of Learned Societies (See Honours above for Fellowships):**

Australian Institute of Physics.

Australian Mathematical Society.

**Research Career:**

I began my career with my much-cited 1970 paper on a general MHD theory of wave-mean flow interaction using Hamilton's Action Principle, using a general formalism I have adapted in my recent first-author publications. This recent work is aimed at generalizing the Multiregion Relaxed MHD approach I and my collaborators developed in a series of Australian Reseearch Council grants leading to the SPEC 3-D MHD equilbrium code. I am currently a founding Principal Investigator for ANU in the international Simons Collaboration on "Hidden Symmetries and Fusion energy". I have a long history of participation in code development and application, being intimately involved with the development of the PPPL/ANU linear MHD stability code series PEST1, PEST2 and PEST3. I have supervised 5 postdocs, 14 PhD, 3 Masters and 2 Honours students to completion. Being a retired Emeritus Professor I am free of university administrative and teaching load and have remained active in research.

**Metrics:**

*Web of Science/Publons*

https://www.webofscience.com/wos/author/record/917070

*Google Scholar*

https://scholar.google.com.au/citations?user=m-hrp8sAAAAJ&hl=en

**Present Appointment:**

Emeritus Professor, The Australian National University (Research School of Physics & Engineering, March 2011 - June 2018; Mathematical Sciences Institute July 2018 - present)**Senior Past Appointments:**

Professor, Level E(1), The Australian National University, October 1992 - July 1996

Professor, Level E(2), Institute of Advanced Studies, Research School of Physics & Engineering (RSPE), ANU, July 1996 - February 2011

Head, Plasma Research Laboratory, RSPhysSE, January 1995 - February 1997

Interim Director, National Plasma Fusion Research Facility, Feb. 1996 - Feb. 1997

Head, Department of Theoretical Physics, RSPhysSE, August 1998 - July 2001

Convenor, ARC Complex Open Systems Research Network (COSNet) 2004 - 2009

## Affiliations

- Computational mathematics, Emeritus
- Fusion plasma theory and modelling, Researcher

## Research interests

I work in the general area of theoretical plasma physics. This field provides a rich array of problems in classical field theory, fluid dynamics, nonlinear dynamics and chaos, and nonequilibrium statistical mechanics. I work mainly in problems related to laboratory plasmas, in particular to the toroidal magnetic confinement approach to the development of fusion power, but have also an interest in space and astrophysical plasmas.

*My current research:* In a recent paper by R.L. Dewar and Z.S. Qu, J. Plasma Phys. **88**, 835880101 (2022), we proposed a variational augmented Lagrangian approach to regularization of the ideal MHD equations in such a way that relaxation of magnetic field line topology is allowed. The basic *hypothesis* of this weak formulation of ideal MHD is that uniform convergence as *L*^{2} tolerance parameters go to zero will fail in neighbourhoods of points where reconnection would occur in a weakly resistive plasma. Relaxation is difficult to simulate using resistive MHD with realistically small resistivity as this is a singular limit. Thus the hope is that weak ideal MHD forms a proxy for resistive MHD that will allow easier and more rapid simulation of reconnection phenomena, allowing magnetic islands and chaos to form as geometric symmetry is broken in the optimization of toroidal magnetic plasma containment devices (stellarators).

The short-term plan is to verify the above hypothesis numerically in a simple plasma geometry and compare it with an alternative Voigt regularization approach by P. Constantin and F. Pasqualotto, arXiv:2208.11109. A longer-term goal is to build new and better 3-D MHD equilibrium, evolution and stability computer codes for use in the Simons Collaboration on stellarator optimization 'Hidden Symmetries and Fusion Energy,' and other physical applications.

### Research projects

- Weak (ideal almost everywhere) formulations of Magnetohydrodynamics (MHD) via regularization methods
- Multi-region relaxation model of self-organization in magnetized three-dimensional plasmas.
- Breakup of invariant (KAM) tori in Hamiltonian systems and its effect on transport -- a problem in classical chaos theory.
- Linear spectrum of waves and instabilities in stellarators -- a classical application of "quantum chaos" theory.

## Location

Room 3.53, Hanna Neumann Building 145

## Publications

- Kumar, A, Nuhrenberg, C, Qu, Z et al. 2022, 'Nature of ideal MHD instabilities as described by multi-region relaxed MHD', Plasma Physics and Controlled Fusion, vol. 64, no. 6.
- Dewar, R & Qu, Z 2022, 'Relaxed magnetohydrodynamics with ideal Ohm's law constraint', Journal of Plasma Physics, vol. 88, no. 1, pp. 1-37.
- Qu, Z, Hudson, S, Dewar, R et al. 2021, 'On the non-existence of stepped-pressure equilibria far from symmetry', Plasma Physics and Controlled Fusion, vol. 63, no. 12.
- Sato, N, Qu, Z, Pfefferle, D et al. 2021, 'Quasisymmetric magnetic fields in asymmetric toroidal domains', Physics of Plasmas, vol. 28, no. 11.
- Kumar, A, Qu, Z, Hole, M et al. 2021, 'Computation of linear MHD instabilities with the multi-region relaxed MHD energy principle', Plasma Physics and Controlled Fusion, vol. 63, no. 4, pp. 1-13.
- Hezaveh Hesar Maskan, H, Qu, Z, Hole, M et al. 2021, 'Theoretical description of chirping waves using phase-space waterbags', Plasma Physics and Controlled Fusion, vol. 63, no. 6.
- Wright, A, Ferraro, N, Hudson, S et al. 2021, 'Predicting nonresonant pressure-driven MHD modes in equilibria with low magnetic shear', Physics of Plasmas, vol. 28, no. 1.
- Qu, Z, Dewar, R, Ebrahimi, F et al. 2020, 'Stepped pressure equilibrium with relaxed flow and applications in reversed-field pinch plasmas', Plasma Physics and Controlled Fusion, vol. 62, no. 5.
- Dewar, R, Burby, J, Qu, Z et al. 2020, 'Time-dependent relaxed

magnetohydrodynamics: Inclusion of cross

helicity constraint using phase-space action', Physics of Plasmas, vol. 27, no. 6, pp. -. - Wright, A, Hudson, A, Dewar, R et al. 2019, 'Resistive stability of cylindrical MHD equilibria with radially localized pressure gradients', Physics of Plasmas, vol. 26, no. 6, pp. 1-9.
- Dewar, R, Hudson, A, Bhattacharjee, A et al. 2017, 'Multi-region relaxed magnetohydrodynamics in plasmas with slowly changing boundaries --- resonant response of a plasma slab', Physics of Plasmas, vol. 24, no. 4, pp. 042507 (19pp).
- Dewar, R L, Tuen, L H & Hole, M J 2017, 'The spectrum of multi-region-relaxed magnetohydrodynamic modes in topologically toroidal geometry', Plasma Physics and Controlled Fusion, vol. 59, no. 4, pp. 044009-1--17. doi:10.1088/1361-6587/aa5b53
- Dewar, R & Hosking, R 2016,
*Fundamental Fluid Mechanics and Magnetohydrodynamics*, Springer, Singapore. - Dewar, R, Yoshida, Z, Bhattacharjee, A et al. 2015, 'Variational formulation of relaxed and multi-region relaxed magnetohydrodynamics', Journal of Plasma Physics, vol. 81, no. 6, p. 515810604.
- Dennis, G, Hudson, A, Dewar, R et al. 2014, 'Multi-region relaxed magnetohydrodynamics with anisotropy and flow', Physics of Plasmas, vol. 21, no. 7, pp. 072512/ 1-10.
- Dennis, G, Hudson, A, Dewar, R et al. 2014, 'Multi-region relaxed magnetohydrodynamics with flow', Physics of Plasmas, vol. 21, no. 4, p. 9.
- Dennis, G, Hudson, A, Dewar, R et al. 2013, 'The infinite interface limit of multiple-region relaxed magnetohydrodynamics', Physics of Plasmas, vol. 20, no. 3, pp. 032509/ 1-6.
- Dennis, G, Hudson, A, Terranova, D et al. 2013, 'Minimally Constrained Model of Self-Organized Helical States in Reversed-Field Pinches', Physical Review Letters, vol. 111, no. 5, p. 055003.
- Dewar, R, Bhattacharjee, A, Kulsrud, R et al 2013, 'Plasmoid solutions of the Hahm-Kulsrud-Taylor equilibrium model', Physics of Plasmas, vol. 20, no. 8.
- Dewar, R, Hudson, S & Gibson, A 2013, 'Generalized action-angle coordinates defined on island chains', Plasma Physics and Controlled Fusion, vol. 55, no. 1, pp. 014004/1-5.
- Hudson, A, Dewar, R, Dennis, G et al. 2012, 'Computation of multi-region relaxed magnetohydrodynamic equilibria', Physics of Plasmas, vol. 19, no. 11, pp. 112502/1-18.
- Dewar, R, Hudson, A & Gibson, A 2012, 'Action-gradient-minimizing pseudo-orbits and almost-invariant tori', Communications in Nonlinear Science and Numerical Simulation, vol. 17, no. 5, pp. 2062-2073.
- Dewar, R & Leykam, D 2012, 'Dressed test particles, oscillation centres and pseudo-orbits', Plasma Physics and Controlled Fusion, vol. 54, no. 1, p. 8.
- Barmaz, D, Cooper, W, McMillan, B et al 2012, 'Diamagnetic drift stabilized ballooning modes in a 3D heliotron', Plasma Physics and Controlled Fusion, vol. 54, no. 1, pp. 1-7.
- Hudson, A, Dewar, R, Hole, M et al. 2012, 'Non-axisymmetric, multi-region relaxed magnetohydrodynamic equilibrium solutions', Plasma Physics and Controlled Fusion, vol. 54, no. 1, pp. 1-7.
- Yoshida, Z & Dewar, R 2012, 'Helical bifurcation and tearing mode in a plasma-a description based on Casimir foliation', Journal of Physics A: Mathematical and Theoretical, vol. 45, no. 36, p. 365502.
- Abdullatif, R & Dewar, R 2011, 'Derivation of the Nonlinear SchrÃ¶dinger Equation by The Derivative Perturbation Expansion Method', International Journal of Basic & Applied Sciences (IJBAS-IJENS), vol. 11, no. 2, pp. 120-124.
- Bertram, J, Hole, M, Pretty, D et al 2011, 'A reduced global Alfven eigenmodes model for Mirnov array data on the H-1NF heliac', Plasma Physics and Controlled Fusion, vol. 53, no. 8, p. 14.
- Dewar, R, Hudson, A & Gibson, A 2010, 'Unified Theory of Ghost and Quadratic-Flux-Minimizing Surfaces', Journal of Plasma and Fusion Research, vol. 9, pp. 487-490.
- Hole, M, von Nessi Jr., G, Bertram, J et al 2010, 'Model Data Fusion: developing Bayesian inversion to constrain equilibrium and mode structure', Journal of Plasma and Fusion Research, vol. 9, pp. 479-486.
- Dewar, R 2010, 'The Screened Field of a Test Particle', in Bruce H J McKellar and Ken Amos (ed.),
*In Celebration of K C Hines*, World Scientific Publishing Company, Singapore, pp. 47-73. - Dewar, R & Detering PhD, F, eds, 2010,
*Complex Physical, Biophysical and Econophysical Systems*, World Scientific Publishing Company, Singapore. - McGann, M, Hudson, S, Dewar, R et al 2010, 'Hamilton-Jacobi theory for continuation of magnetic field across a toroidal surface supporting a plasma pressure discontinuity', Physics Letters A, vol. 374, no. 33, pp. 3308-3314.
- Hole, M, Mills, R, Hudson, A et al. 2009, 'Relaxed MHD states of a multiple region plasma', Nuclear Fusion, vol. 49, no. 065019, p. 7.
- Hudson, A & Dewar, R 2009, 'Are ghost surfaces quadratic-flux-minimizing?', Physics Letters A, vol. 373, pp. 4409-4415.
- Dewar, R, Mills, R & Hole, M 2009, 'MHD memes',
*Plasma theory, wave kinetics, nonlinear dynamics: Kaufmanfest 2007*, ed. IOP, Institute of Physics Publishing, USA, p. 8. - Dewar, R & Yap, J 2009, 'Adiabatic Wave-Particle Interaction Revisited', Plasma and Fusion Research, vol. 4, no. 001, pp. 1-6.
- Mills, R, Hole, M & Dewar, R 2009, 'Magnetohydrodynamic stability of plasmas with ideal and relaxed regions', Journal of Plasma Physics, vol. 75, no. 5, pp. 637-659.
- Dewar, R, Hole, M, McGann, M et al. 2008, 'Relaxed Plasma Equilibria and Entropy-Related Plasma Self-Organization Principles', Entropy, vol. 10, pp. 621-634.
- Blackwell, B, Pretty, D, Howard, J et al. 2008, 'Configurational Effects on Stability and Confinement in the H-1NF Heliac',
*International Atomic Energy Agency Fusion Energy Conference (FEC 2008)*, International Atomic Energy Agency (IAEA), Geneva. - Dewar, R, Nuehrnberg, C, Tatsuno, T et al 2007, 'Quantum Chaos? Genericity and Nongenericity in the MHD Spectrum of Nonaxisymmetric Toroidal Plasmas', Journal of the Korean Physical Society, vol. 50, no. 1, pp. 112-117.
- Dewar, R & Abdullatif, R 2007, 'Zonal Flow Generation by Modulational Instabiity', in Jim Denier & Jorgen Fredericksen (ed.),
*Frontiers in Turbulence and Coherent Structures: proceedings of the COSNet/CSIRO Workshop on Turbulence and Coherent Structures in Fluids, Plasmas and Nonlinear Media*, World Scientific Publishing Company, New Jersey, USA, pp. 415-430. - Numata, R, Ball, R & Dewar, R 2007, 'Bifurcation in Electrostatic Resistive Drift Wave Turbulence', Physics of Plasmas, vol. 14, pp. 102312 1-8.
- Numata, R, Ball, R & Dewar, R 2007, 'Nonlinear Simulation of Drift Wave Turbulence', in Jim Denier & Jorgen Fredericksen (ed.),
*Frontiers in Turbulence and Coherent Structures: proceedings of the COSNet/CSIRO Workshop on Turbulence and Coherent Structures in Fluids, Plasmas and Nonlinear Media*, World Scientific Publishing Company, New Jersey, USA, pp. 431-442. - Hole, M, Hudson, A & Dewar, R 2007, 'Equilibria and stability in partially relaxed plasma-vacuum systems', Nuclear Fusion, vol. 47, no. 8, pp. 746-753.
- Hudson, A, Hole, M & Dewar, R 2007, 'Eigenvalue problems for Beltrami fields arising in a three-dimensional toroidal magnetohydrodynamic equilibrium problem', Physics of Plasmas, vol. 14, pp. 052505 1-12.
- Hole, M, Hudson, A & Dewar, R 2006, 'Stepped Pressure Profile Equilibria in Cylindrical Plasmas via Partial Taylor Relaxation', Journal of Plasma Physics, vol. 72, no. 6, pp. 1167-1171.
- Dewar, R, Nuehrenberg, C & Tatsuno, T 2006, 'Quantum Chaos Analysis of the Ideal Interchange Spectrum in a Stellarator', Journal of Plasma Physics, vol. 72, no. 6, pp. 1239-1242.
- Hole, M, Hudson, A & Dewar, R 2006, 'Equilibria and stability in partially relaxed plasma-vacuum systems

',*International Atomic Energy Agency Fusion Energy Conference (FEC 2006)*, Conference Organising Committee, Website. - McMillan, B & Dewar, R 2006, 'Stellarator Stability with Respect to Global Kinetic Ballooning Modes', Nuclear Fusion, vol. 46, pp. 477-486.
- McMillan, B & Dewar, R 2005, 'Stability for Kinetic Ballooning Modes in Stellarators',
*National Congress Australian Institute of Physics 2005*, ed. Max Colla, Australian Institute of Physics, Canberra, pp. 235-1-4. - Dewar, R, McMillan, B & Kenny, B 2005, 'Spacing Statistics of Model Spectra Related to Farey Sequences',
*National Congress Australian Institute of Physics 2005*, ed. Max Colla, Australian Institute of Physics, Canberra, pp. PTH 41. - Dewar, R, Nuehrnberg, C & Tatsuno, T 2004, 'Quantum Chaos Theory and the Spectrum of Ideal-MHD Instabilities in Toroidal Plasmas',
*International Toki Conference (ITC 2004)*, ed. K. Ichiguchi, M. Yokoyama, T Hayashi, Japan Society of Plasma Science and Nuclear Fusion Research, Japan, pp. 40-44. - Dewar, R & McMillan, B 2004, 'Finite Larmor Radius Effects and Quantum Chaos',
*International Congress on Plasma Physics (ICCP 2004)*, Conference Organising Committee, OnLine, pp. online. - McMillan, B, Dewar, R & Storer, R 2004, 'A Comparison of Incompressible Limits for Resistive Plasmas', Plasma Physics and Controlled Fusion, vol. 46, pp. 1027-1038.
- Dewar, R, Abdullatif, R & Gnanapragasam, G 2004, 'Complex Nonlinear Lagrangian for the Hasegawa-Mima Equation',
*International Atomic Energy Agency Fusion Energy Conference (FEC 2004)*, ed. Guenter Mank & Artur Malaquias, International Atomic Energy Agency (IAEA), online, pp. P6-1. - Dewar, R, Tatsuno, T, Yoshida, Z et al. 2004, 'Statistical Characterization of the Interchange-Instability Spectrum of a Separable Ideal-Magnetohydrodynamic Model System', Physical Review E-Statistical, Nonlinear and Soft Matter Physics, vol. 70, no. 6, pp. 066409 (11).
- Dewar, R 2003, 'Spectrum of Global Ideal-magnetohydrodynamic Three-dimensional Ballooning Modes', Space Science Reviews, vol. 107, no. 1-2, pp. 349-352.
- McMillan, B, Dewar, R & Storer, R 2003, 'A Broken Degeneracy in the Resistive MHD Spectrum', in I.S. Falconer, R.L. Dewar, J. Khachan (ed.),
*Plasma Physics: Proceedings of the 11th International Congress on Plasma Physics, ICPP2002*, American Institute of Physics (AIP), New York, pp. 577-580. - Kendl, A, Scott, B, Ball, R et al 2003, 'Turbulent Edge Structure Formation in Complex Configurations', Physics of Plasmas, vol. 10, pp. 3684-3691.
- Ball, R, Dewar, R & Sugama, H 2003, 'Bifurcation and Metamorphosis of Plasma Turbulence-Shear Flow Dynamics: The Path to the Top of the Hill', in I.S. Falconer, R.L. Dewar, J. Khachan (ed.),
*Plasma Physics: Proceedings of the 11th International Congress on Plasma Physics, ICPP2002*, American Institute of Physics (AIP), New York, pp. 711-714. - Falconer, I, Dewar, R & Khachan, J, eds, 2003,
*Proceedings of the 11th International Congress on Plasma Physics, ICPP 2002*, American Institute of Physics (AIP), New York. - Redi, M, Johnson, J, Klasky, S et al 2002, 'Anderson Localization of Ballooning Modes, Quantum Chaos and the Stability of Compact Quasiaxially Symmetric Stellarators', Physics of Plasmas, vol. 9, no. 5, pp. 1990-1996.
- Dewar, R 2002, 'Asymptotology - A Cautionary Tale', ANZIAM Journal, vol. 44, pp. 33-40.
- Ball, R, Dewar, R & Sugama, H 2002, 'Metamorphosis of Plasma Turbulence-shear-flow Dynamics through a Transcritical Bifurcation', Physical Review E, vol. 66, no. 6, pp. 066408-1-9.
- Ball, R & Dewar, R 2001, 'A Walk in the Parameter Space of L-H Transitions without Stepping on or Through the Cracks', Journal of Plasma and Fusion Research, no. 4, pp. 266-270.
- Dewar, R, Cuthbert, P & Ball, R 2001, 'Strong "Quantum" Chaos in the Global Ballooning Mode Spectrum of Three-Dimensional Plasmas', Physical Review Letters, vol. 86, no. 11, pp. 2321-2324.
- Ball, R, Dewar, R & Sugama, H 2001, 'Symmetry and singularities in a low-dimensional model of a complex system. A back door approach to the physics of L-H transitions',
*IPELS-2001*, ed. Sato, T., National Institute for Fusion Science, Toki, Japan, pp. 73-76. - Dewar, R & Cuthbert, P 2000, 'Anderson Localization and Ballooning Eigenfunctions', Chinese Physics Letters, pp. 33-35.
- Cuthbert, P & Dewar, R 2000, 'Anderson-Localized Ballooning Modes in General Toroidal Plasmas', Physics of Plasmas, vol. 7, no. 6, pp. 2302-2305.
- Stewart, D & Dewar, R 2000, 'Non-Linear Dynamics', in Green, Terry R J Bossomaier & David G (ed.),
*Complex Systems*, Cambridge University Press, Cambridge, pp. 165-249. - Ball, R & Dewar, R 2000, 'Singularity Theory Study of Overdetermination in Models for L-H Transitions', Physical Review Letters, vol. 84, pp. 3077-3080.
- Hudson, A & Dewar, R 1999, 'Analysis of Perturbed Magnetic Fields via Construction of Nearby Integrable Fields', Physics of Plasmas, vol. 6, pp. 1532-1538.
- Dewar, R & Ciubotariu, C 1999, 'Quasilinear theory of collisionless Fermi Acceleration in a multicusp magnetic confinement geometry', Physical Review E-Statistical, Nonlinear and Soft Matter Physics, vol. 60, no. 6, pp. 7400-7411.
- Zimin, S, Cross, R & Dewar, R 1999, 'Overview of Australian Activities of Fusion Neutronics', Fusion Engineering and Design, vol. 45, pp. 117-126.