📝 SummarXiv

Abstract

In a shallow-water radial outflow the horizon of a hydrodynamic white hole coincides with a standing circular hydraulic jump. The jump, caused by viscosity, makes the horizon visible as a circular front, standing as a barrier against the entry of waves within its circumference. The blocking of waves causes a pile-up at the horizon of the white hole, for which surface tension is mainly responsible. Conversely, it is also because of surface tension that the waves can penetrate the barrier. The penetrating waves (analogue Hawking quanta) tunnel through the barrier with a decaying amplitude, but a large-amplitude instability about the horizon is possible.