Beyond the present understanding of spontaneous organization in fluids and plasmas: a field theoretical approach.

This is the web page of the Contract 4 ERC - Like supported by the Executive Unit for Financing Higher Education, Research, Development and Innovation (UEFISCDI)

Summary of the project

Almost all studies of fluids are based on few notions: streamfunction, velocity, vorticity, and use conservation equations regarded as dynamical equations. However it is well established that two-dimensional fluids and plasmas exhibit an intrinsic evolution to organisation, for example at relaxation from turbulent states to coherent structures. This means that priviledged states exist and we need an approach based on extrema of functionals defined on the space of system's configurations. We have developed such an approach, applied it to Euler fluids, to planetary atmosphere and to magnetically confined plasma. It is a field theoretical (FT) formulation, in terms of a Lagrangian for fluids/plasmas. Writting a Lagrangian was possible due to a particularity of 2D: the existence of equivalent discrete models of interacting point-like vortices. We found that the continuum limit of these discrete models can be formalized in terms of a Lagrangian density, preserving the structure: matter (point-like vortices), field (from potential) and their interaction. The result is a classical field theory and the powerful technics of the FT considerably extended the description of fluid, plasma systems. Our results have good comparison with experiment. We propose to investigate the Field Theoretical formulation for fluids/plasmas and to apply it to tropical cyclones, vortical flows in plasma, vorticity concentration in fluids, which are inaccessible to usual approaches. In the opposite direction, fluids offer intuitive representations for complex pure-FT problems: axial anomaly, mass generation by spontaneous chiral symmetry breaking, etc. We propose to investigate these deep connections. This will represent a considerable change in our understanding of the fluid physics, in the concepts and terms of investigation and in our technical methods .

Final Report

We have made a series of Seminars. Several participations to conferences. Collaborations with colleagues from several countries. A visit of a French scientist to Bucharest. One publication and three more in preparation.

Few of our previous works on this subject