Group transformation for phase space fluids

J.R. Burgan (1, 2) , J. Guttierez (1) , A. Munier (1) , E. Fijalkow (1) , M.R. Feix (1, 2)

1 CRPE - Centre de recherches en physique de l'environnement terrestre et planétaire
2 LPCE - Laboratoire de physique et chimie de l'environnement

We want to study the time behaviour of Systems where long distances forces are predominant. Such is the case of plasmas, accelerator beam (where we are dealing with Coulomb forces plus electromagnetic confinning external fields) and self gravitating gas (galaxy, cluster of stars etc...) where the Newtonian attraction compete against the thermal (ballistic)expansion. In many cases we can disregard the small irregularities due to the grain structure of the matter (with grain as big as a star in a galaxy) and describe the interaction through a continuous field obtained by the solution of the Poisson equation. This is the well known Vlasov Poisson structure where the global description is obtained by considering the distribu- tion function f (x,v, t) in the 6 dimensional phase space in contradiction to a regular gas where we can usually deal with the first moments of f with respect to v (particles density, momentum, energy density etc...). Consequently we call phase space fluids such Systems. A discussion of the relative properties of these a priori very différent fluids is given in 111 and 121. From the model's maker point of view adopted hère they présent great similarities.

Domaines: Sciences de la Terre

J.R. Burgan, J. Guttierez, A. Munier, E. Fijalkow, M.R. Feix. Group transformation for phase space fluids. [Research Report] Note technique CRPE n° 47, Centre de recherches en physique de l'environnement terrestre et planétaire (CRPE). 1977, 50 p. ⟨hal-02191403⟩