  We present a theoretical study of the spontaneous emission of a line dipole
source embedded in a graphene--coated subwavelength wire of arbitrary shape.
The modification of the emission and the radiation efficiencies are calculated
by means of a rigorous electromagnetic method based on Green's second identity.
Enhancement of these efficiencies is observed when the emission frequency
coincides with one of the plasmonic resonance frequencies of the wire. The
relevance of the dipole emitter position and the dipole moment orientation are
evaluated. We present calculations of the near--field distribution for
different frequencies which reveal the multipolar order of the plasmonic
resonances.
