SELF-ORGANIZATION AND COHERENT STRUCTURES IN PLASMAS AND FLUIDS

Citation
Ah. Nielsen et al., SELF-ORGANIZATION AND COHERENT STRUCTURES IN PLASMAS AND FLUIDS, Physica scripta. T, T63, 1996, pp. 49-58
Citations number
72
Categorie Soggetti
Physics
Journal title
ISSN journal
02811847
Volume
T63
Year of publication
1996
Pages
49 - 58
Database
ISI
SICI code
0281-1847(1996)T63:<49:SACSIP>2.0.ZU;2-W
Abstract
The formation and dynamics of vortical structures in two-dimensional f lows are investigated numerically and theoretically. Localized initial distributions with random fluctuations are in general found to evolve into large scale vortical structures. If the initial perturbation con tains a linear momentum the development into propagating dipolar struc tures is observed. This development is discussed by employing self-org anization principles. The detailed structures of the evolving dipoles depends on the initial condition. It seems that there are no unique di polar solutions, but a large class of solutions is possible. However, it is argued that the gross properties of the dipoles do not depend cr itically on the detailed structure. The vortical structures are found to trap particles and convect them over distances much larger than the scale size of the structure. Two examples of trapping/detrapping of p articles are shown. The trapping of particles by a decaying, expanding dipolar vortex and the detrapping of particles during the merging of two Like-signed monopolar vortices.