Rotational superradiant scattering in a vortex flow
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, k...
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| Format: | Article |
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Nature Publishing Group
2017
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| Online Access: | https://eprints.nottingham.ac.uk/43862/ |
| _version_ | 1848796784669753344 |
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| author | Torres, Theo Patrick, Sam Coutant, Antonin Richartz, Mauricio Tedford, Edmund W. Weinfurtner, Silke |
| author_facet | Torres, Theo Patrick, Sam Coutant, Antonin Richartz, Mauricio Tedford, Edmund W. Weinfurtner, Silke |
| author_sort | Torres, Theo |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | 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 1, 2, 3, 4. 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% ± 8%, obtained for 3.70 Hz waves, in a 6.25-cm-deep fluid, consistent with the superradiant scattering caused by rapid rotation. We expect our experimental findings to be relevant to black-hole physics, since shallow water waves scattering on a draining fluid constitute an analogue of a black hole 5, 6, 7, 8, 9, 10, as well as to hydrodynamics, due to the close relation to over-reflection instabilities 11, 12, 13. |
| first_indexed | 2025-11-14T19:53:29Z |
| format | Article |
| id | nottingham-43862 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:53:29Z |
| publishDate | 2017 |
| publisher | Nature Publishing Group |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-438622020-05-04T19:55:57Z https://eprints.nottingham.ac.uk/43862/ Rotational superradiant scattering in a vortex flow Torres, Theo Patrick, Sam Coutant, Antonin Richartz, Mauricio Tedford, Edmund W. Weinfurtner, Silke 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 1, 2, 3, 4. 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% ± 8%, obtained for 3.70 Hz waves, in a 6.25-cm-deep fluid, consistent with the superradiant scattering caused by rapid rotation. We expect our experimental findings to be relevant to black-hole physics, since shallow water waves scattering on a draining fluid constitute an analogue of a black hole 5, 6, 7, 8, 9, 10, as well as to hydrodynamics, due to the close relation to over-reflection instabilities 11, 12, 13. Nature Publishing Group 2017-09 Article PeerReviewed Torres, Theo, Patrick, Sam, Coutant, Antonin, Richartz, Mauricio, Tedford, Edmund W. and Weinfurtner, Silke (2017) Rotational superradiant scattering in a vortex flow. Nature Physics, 13 . pp. 833-836. ISSN 1745-2481 Fluid dynamics High-energy astrophysics https://doi.org/10.1038/nphys4151 doi:10.1038/nphys4151 doi:10.1038/nphys4151 |
| spellingShingle | Fluid dynamics High-energy astrophysics Torres, Theo Patrick, Sam Coutant, Antonin Richartz, Mauricio Tedford, Edmund W. Weinfurtner, Silke Rotational superradiant scattering in a vortex flow |
| title | Rotational superradiant scattering in a vortex flow |
| title_full | Rotational superradiant scattering in a vortex flow |
| title_fullStr | Rotational superradiant scattering in a vortex flow |
| title_full_unstemmed | Rotational superradiant scattering in a vortex flow |
| title_short | Rotational superradiant scattering in a vortex flow |
| title_sort | rotational superradiant scattering in a vortex flow |
| topic | Fluid dynamics High-energy astrophysics |
| url | https://eprints.nottingham.ac.uk/43862/ https://eprints.nottingham.ac.uk/43862/ https://eprints.nottingham.ac.uk/43862/ |