  We characterize the spatial optical solitons supported by arrays of metallic
nanowires embedded in Kerr-type material. The array of nanowires is described
using an effective medium model and is regarded as a continuous medium. It is
shown that the conditions necessary for the formation of spatial-solitons are
radically different in presence of the nanowires, and in particular within the
effective medium model spatial-solitons are allowed in the nanowire material
only in case the host material is a "self-defocusing" material. It is proven
that the characteristic soliton beamwidth is related to the degree of
hyperbolicity of the isofrequency surfaces of the photonic states, and that a
sufficiently strong electric field amplitude may enable subwavelength solitary
waves.
