Self-focusing and envelope pulse generation in nonlinear magnetic   metamaterials
  The self-modulation of waves propagating in nonlinear magnetic metamaterials is investigated. Considering the propagation of a modulated amplitude magnetic field in such a medium, we show that the self-modulation of the carrier wave leads to a spontaneous energy localization via the generation of localized envelope structures (envelope solitons), whose form and properties are discussed. These results are also supported by numerical calculations. 
I. Kourakis, N. Lazarides and G. P. Tsironis