Formation of 'clusters' of vortices on a sphere

This paper applies the Hamiltonian approach to the two-dimensional motion o f an incompressible fluid on a curvilinear surface. The method has been use d to formulate governing equations of motion, and to interpret the evolutio n of a system consisting of N similar to 10(2)-10(3) localized two-dimensio nal Vortices on a sphere. The analysis shows that the instability appears i mmediately, forming initial disorganized structures which develop and final ly 'burst'. The system evolves to a few separated vortex 'spots' which are quasi-stable. (C) 2001 Academie des sciences/Editions scientifiques et medi cales Elsevier SAS.