In Putterman's Scientific American paper http://www.physics.ucla.edu/Sonoluminescence/sono.pdf
which has already been referred to in a previous post in this thread, there is a diagram of the sonoluminescence spectrum. Under the diagram is the following caption ============================================= SPECTRUM of sonoluminescence shows that most of the emitted light is ultraviolet. As pointed out by Paul H Roberts and Cheng- Chin Wu of the University of California at Los Angeles, the signal compares closely with the bremsstrahlung radiation - that is, light emitted by a plasma of 100,000 kelvins. ============================================= Now what on earth is the connection between a collimated bremsstrahlung radiation (BR) beam in a synchrotron and sonoluminescence (SL). Hydrodynamics gives the answer. In both cases we have a B-a pressure drop. In the synchrotron case is it a Bernoulli pressure drop in the electron stream. In the SL case it is a pressure drop inside the high pF cavitation hole within the water. Interestingly enough, seeing BR as a hydrodynamic phenomena neatly explains something which I've never understood before, i.e. why BR produces a searchlight type beam in the synchrotron. The transition from streamline flow in a pipe (parabolic velocity distribution) to turbulent flow (uniform velocity distribution) can be seen as a transition from isotropic micro vortices with their axes perpendicular to the direction of flow to vortices with their axes parallel to the flow direction. Now if BR electron orbits are oriented in the same manner as turbulent flow vortices then a collimated beam can be expected. Cheers Frank Grimer
