Self-duality of the asymptotic relaxation states of fluids and plasmas
  The states of asymptotic relaxation of 2-dimensional fluids and plasma present a high degree of regularity and obey to the sinh-Poisson equation. We find that embedding the classical fluid description into a field-theoretical framework, the same equation appears as a manifestation of the self-duality. 
F. Spineanu and M. Vlad