1. Some observations on the initiation and onset of detonation by Geraint Thomas Philosophical Transactions A Volume 370(1960):715-739 February 13, 2012 ©2012 by The Royal Society

2. Spark schlieren images of (a) a turbulent flame and (b) a detonation. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

3. Predicted cell widths (open squares) and peak measured wavefront pressure (filled circles) versus nitrogen dilution in (a) ethylene–oxygen and (b) silane-nitrous oxide. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

4. (a) Smoked foil and (b) sketch of direct initiation of a hemispherical detonation. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

5. (a) Smoked foil of direct initiation of a cylindrical detonation. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

6. (a) Streak schlieren image and (b) sketch of key features observed during the direct planar shock initiation of a detonation. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

7. Pressure records showing the temporal evolution of pressure at a number of gauge locations in a 30 m long, 0.15 m diameter pipe filled with: (a) ethylene in air and (b) hydrogen in air. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

8. Spark schlieren images of detonation diffraction from a rectangular channel: (a) subcritical transmission, (b) critical transmission and (c) supercritical transmission. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

9. Numerical simulations of a diffracting detonation. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

10. Sequence of schlieren images showing the initial distortion of the flame bubble by an incident shock (mixture C2H4+3O2+4N2, incident shock Mach number 1.7, frame interval 50 μs). Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

11. Sequence of schlieren images of shock–flame interactions for an incident shock Mach number of 2.5, mixture composition C2H4+3O2+4N2, frame interval of 10 μs. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

12. Spark schlieren images showing the emergence of detonation in reflected shock region, gas mixture C2H4+3O2+12 Ar. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

13. Numerical simulation output showing development of conditions conducive to onset of detonation following turbulent flame acceleration in a long pipe, open at one end. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society

14. Sketch illustrating different modes of high and low source energy and associated key blast or flame-acceleration processes that can lead to detonation in a reactive medium. Geraint Thomas Phil. Trans. R. Soc. A 2012;370:715-739 ©2012 by The Royal Society