Cylindrical Korteweg-de Vries solitons on a ferrofluid surface

Linear and non-linear surface waves on a ferrofluid cylinder surrounding a current-carrying wire are investigated. Suppressing the Rayleigh-Plateau instability of the fluid column by the magnetic field of a sufficiently large current in the wire axis-symmetric surface deformations are shown to propagate without dispersion in the long wavelength limit. Using multiple scale perturbation theory the weakly non-linear regime may be described by a Korteweg-de Vries equation with coefficients depending on the magnetic field strength. For different values for the current in the wire hence different solutions such as hump or hole solitons may be generated. The possibility to observe these structures in experiments is also elucidated.