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What is a shock wave?

A shock wave is a very strong pressure wave in any elastic medium, produced by supersonic craft, lightning, explosions, or other extreme phenomena that create sudden, huge changes in pressure. The shock front, which is a narrow region in the fluid over which its thermodynamic state changes markedly. The thickness of the front is of order a few mean free paths in the medium ahead of the wave.

Of course, shock waves are present in many other situations as well. An every day experience with shock waves, may be when you are travelling to and from work in your car. As the traffic lights turn red, the cars are forced to break one after each other and that "wave of breaking cars" is a shock wave.

What is sonoluminescense?

Sonoluminescence is the emission of short bursts of light from imploding bubbles in a liquid when excited by sound. Sonoluminescence was first discovered at the University of Cologne in 1934 as a result of work on sonar by H. Frenzel and H. Schultes. In 1989, single bubble sonoluminescence (SBSL) was produced Felipe Gaitan and Lawrence Crum. SBSL is when a single bubble, trapped in an acoustic standing wave, emits a pulse of light with each compression of the standing wave.

Shock waves and light emission?

My research project was about shock wave focusing and light emission. We were looking at how the shape of a converging shock wave influences the dynamics and the stability during the focusing and reflection phase. Also, when a shock wave is focused, light is emitted. The amount of light is dependent on the shape and the stability of the shock wave. These subjects were the main issues I have been working on during my Ph. D. The thesis is available for download here.

Read more about the project at KTH's project database.