Hawking radiation in moving plasmas

TL;DR

This paper demonstrates the emergence of Hawking radiation and bi-metricity in non-relativistic moving magnetohydrodynamics (MHD) plasmas, revealing effective black hole horizons in a plasma medium with two distinct Riemannian metrics.

Contribution

It introduces a novel analysis of Hawking radiation in MHD plasmas with two effective metrics, one flat and one with a horizon, expanding analog gravity models to plasma physics.

Findings

Identification of two effective metrics in MHD plasma

Hawking radiation associated with the horizon metric

Analogy to optical black holes in moving dielectrics

Abstract

Bi-metricity and Hawking radiation are exhibit in non-relativistic moving magnetohydrodynamics (MHD) plasma medium generating two Riemannian effective spacetimes. The first metric is a flat metric although the speed of "light" is given by a time dependent signal where no Hawking radiation or effective black holes are displayed. This metric comes from a wave equation which the scalar function comes from the scalar potential of the background velocity of the fluid and depends on the perturbation of the magnetic background field. The second metric is an effective spacetime metric which comes from the perturbation of the background MHD fluid. This Riemann metric exhibits a horizon and Hawking radiation which can be expressed in terms of the background constant magnetic field. The effective velocity is given Alfven wave velocity of plasma physics. The effective black hole found here is analogous to the optical black hole in moving dielectrics found by De Lorenci et al [Phys. Rev. D (2003)] where bi-metricity and Hawking radiation in terms of the electric field are found.