Field theoretical approach to the description of the coherent structures in 2 D fluids and plasmas

Evolving from turbulent states the 2D fluids and the plasmas reach states characterized by a high degree of order, consisting of few vor-tices. These asymptotic states represent a small subset in the space of functions and are characterised by properties that are difficult to identify in a direct approach. The field theoretical approach to the dynamics and to the asymptotic states of fluids and plasmas in 2D provides a considerable extension of the usual perspective. The present works discusses a series of consequences of the field theoretical approach, when it is applied to particular problems. The discussion is developed around known physical problems: the current density profiles in cylindrical plasma, the density pinch in tokamak and the concentration of vorticity.