Oral Presentation

Analogue superradiance for MHD waves

Author(s): Sousuke Noda (Nagoya University), Yasusada Nambu (Nagoya University), Masaaki Takahashi (Aichi University of Education)

Presenter: Sousuke Noda (Nagoya university)

Even in the case of flat spacetime, the equation for sound wave on a back ground flow can be written as Klein Gordon equation in an effective curved spacetime whose metric is called acoustic metric. The acoustic metric depends on the back ground flow and if we consider bathtub-like flow which is stationary and axisymmetric and has a sink at the center of the flow, the effective geometry is described by Kerr-like metric. So we can evaluate superradiant scattering of sound wave in terms of the ordinary superradiance in general relativity. In this presentation, we generalize the above discussion to magnetohydrodynamics. Then we discuss the possibility of application to some astrophysical phenomena.