  We consider an irrotational plasma fluid evolving under the effect of a
background magnetic field. The magnetohydrodynamic formalism is used to
describe the electromagnetic waves and the dynamics is described by a scalar
field that follows a second order differential equation. This equation can also
be recovered as the wave equation associated to a field in a curved space-time.
Through this analogy we recreate a sonic horizon, equivalent to those found in
perfect fluid theories. However, in this case, the magnetic field creates a
pressure in the plasma which contributes to the magnetoacoustic speed that
builds the horizon. This effect enhances the temperature produced by the
Hawking radiation expected from this analogue black hole, and eventually,
making its experimental detection worth to consider.
