Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hawking radiation in moving plasmas   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.

22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
19
The categories of this paper are: eess
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph