Two-dimensional solitons on the surface of magnetic fluids
  We report an observation of a stable soliton-like structure on the surface of a ferrofluid, generated by a local perturbation in the hysteretic regime of the Rosensweig instability. Unlike other pattern-forming systems with localized 2D structures, magnetic fluids are characterized by energy conservation; hence their mechanism of soliton stabilization is different from the previously discussed gain/loss balance mechanism. The radioscopic measurements of the soliton's surface profile suggest that locking on the underlying periodic structure is instrumental in its stabilization. 
Reinhard Richter and I.V. Barashenkov