University of Cambridge > > Institute of Astronomy Colloquia > Rotational superradiant scattering in a vortex flow

Rotational superradiant scattering in a vortex flow

Add to your list(s) Download to your calendar using vCal

If you have a question about this talk, please contact Simon Hodgkin.

When an incident wave scatters off of an obstacle, it is partially reflected and partially transmitted. In theory, if the obstacle is rotating, waves can be amplified in the process, extracting energy from the scatterer. Here we describe in detail the first laboratory detection of this phenomenon, known as superradiance. We observed that waves propagating on the surface of water can be amplified after being scattered by a draining vortex. The maximum amplification measured was 14%, obtained for 3.70 Hz waves, in a 6.25 cm deep fluid, in consistency with superradiant scattering caused by rapid rotation.  Our experimental findings will shed new light not only on Black Hole Physics, since shallow water waves scattering on a draining fluid constitute an analogue of a black hole, but also on hydrodynamics, due to its close relation to over-reflection instabilities. We believe, in view of the recent detections of gravitational waves, that our results will motivate further research on the observation of superradiance in Astrophysics.

This talk is part of the Institute of Astronomy Colloquia series.

Tell a friend about this talk:

This talk is included in these lists:

Note that ex-directory lists are not shown.


© 2006-2017, University of Cambridge. Contact Us | Help and Documentation | Privacy and Publicity