Dr Samuel Drake

Adjunct Associate Lecturer
Dr Samuel Drake
  Org Unit Physics
  Email samuel.drake@adelaide.edu.au
  Location Floor/Room G 18 ,  Physics Building ,   North Terrace

Engineer by day, physicist by night

I am a senior research scientist within the Australian Public Service. I also currently hold an adjunct associate lecturer position in the Department of Physics, School of Chemistry and Physics at Adelaide University


  • Swinburne Community School
  • Camberwell High School
  • Melbourne University
  • University of Padua, Italy
  • Adelaide University

  • Bachelor of Science (First Class Honours); majoring in Physics; University of Melbourne, Australia
  • Doctor of Philosophy; Physics;  University of Adelaide, Australia
  • Graduate Diploma in Scientific Leadership; University of Melbourne, Australia

 I currently lecture Application of Relativity to honours level physics students.


Drake, S. P., C. P. Dettmann, et al. (1996). "Chaos in special relativistic dynamics." Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics 53(2): 1351-1361.
The study of chaos in relativistic systems (both special and general) is a newly emergent field. The main focus of this paper is the study of the chaotic trajectories of a charged particle in a static electric field. The full special relativistic equations of motion are used. Here we concentrate on motion in a field that is produced by two fixed centers with equal charge. The chaotic nature of these trajectories is investigated by examining the fractal nature of the attractor basin boundary. An examination of how these properties change with respect to fundamental parameters of the problem, such as charges, mass and charge separation, is undertaken. We emphasize that fractal basin boundaries provide an important characterization of chaos in relativistic dynamics

Drake, S. P. (2003). "The Formation of Non-Keplerian Rings of Matter about Compact Stars." General Relativity and Gravitation 35(1): 43-58.
The formation of energetic rings of matter in a Kerr spacetime with an outward pointing acceleration field does not appear to have previously been noted as a relativistic effect. In this paper we show that such rings are a gravimagneto effect with no Newtonian analog, and that they do not occur in the static limit. The energy efficiency of these rings can (depending of the strength of the acceleration field) be much greater than that of Keplerian disks. Counter-intuitively these rings rotate in a direction opposite to that of compact star about which they form. The size and energy efficiency of the rings depend on the fundamental parameters of the spacetime as well as the strength the acceleration field.

Drake, S. P. (2006). "The equivalence principle as a stepping stone from special to general relativity: A Socratic dialog." American Journal of Physics 74(1): 22-25.
We show how students can be led to an understanding of the connection between special relativity and general relativity by considering the time dilation effect of clocks placed on the surface of the Earth. This paper is written as a Socratic dialog between a lecturer and a student.

This work is referenced at the Einstein Light web site, a site devoted to the explanation of special relativity.

Passive Localization and Tracking

Drake, S. and K. Dogancay (2004). Geolocation by Time Difference of Arrival Using Hyperbolic Asymptotes. Proc. IEEE Int. Conf. on Acoustics, Speech, and Signal Processing.
The paper proposes a new simplified algorithm to estimate the location of an emitter by utilizing time difference of arrival (TDOA) measurements. This is achieved by recasting the estimation problem in prolate spheroidal coordinates. Prolate spheroidal coordinates greatly simplify the TDOA equations, producing a set of linear equations in the far field limit. The set of linear equations corresponds to the hyperbolic asymptotes of the TDOA measurements. We also develop a systematic approach that associates the hyperbolic asymptotes with the emitter. In the near field the far- field solution can be used to 'seed' the iterative maximum likelihood (ML) estimate, enabling convergence to the ML solution.

Relativity meets Localization and Tracking

Drake, S. P., B. D. O. Anderson, et al. (2009). "Causal association of electromagnetic signals using the Cayley--Menger determinant." Applied Physics Letters 95(3): 034106-3.
In complex electromagnetic environments it can often be difficult to determine whether signals received by an antenna array emanated from the same source. The failure to appropriately assign signal reception events to the correct emission event makes accurate localization of the signal source impossible. In this paper we show that as the received signal events must lie on the light-cone of the emission event the Cayley–Menger determinate calculated from using the light-cone geodesic distances between received signals must be zero. This result enables us to construct an algorithm for sorting received signals into groups corresponding to the same far-field emission

This work is the subject of patents in

Science on the radio

Physics Songs

Podcasts I subscribe to

Selected episodes

Research funding in Australia
David Blair presents the case for increased funding for university research programs. He describes the process of grant applications, the small success rate and the meagre level of funding available. He says the current system is a national tragedy.
In Two Minds - Part 1
If you've ever used the expression in two minds to describe a feeling of indecision there may be a physiological reason for it. Professor Jack Pettigrew's research gives some fascinating insights into the functioning of the two hemispheres of our brain. The two hemispheres of our brain and the blue ball and Bonneh's Illusions.
English has so many origins and variations that it's the most difficult language for a child to learn, especially if he or she is tending towards dyslexia.
Welcome to gravitational astronomy 101
Today's Ockham's razor is set 50 years into the future with Professor David Blair from the School of Physics at the University of Western Australia welcoming students to a new course in astronomy. The threat of a cosmic bullet threatening life on earth is very real and a sound knowledge of gravitational astronomy in 2059 will be crucial to our survival.



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Entry last updated: Tuesday, 16 Feb 2016

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