HR: 0800h
AN: SM51B-1286    [Abstracts]
TI: Closure of Fluid Equations in Collisionless Magnetoplasmas
AU: * Chust, T
EM: thomas.chust@cetp.ipsl.fr
AF: CETP/CNRS-UVSQ/IPSL, 10-12 avenue de l'Europe, Vélizy, 78140 France
AU: Belmont, G
EM: gerard.belmont@cetp.ipsl.fr
AF: CETP/CNRS-UVSQ/IPSL, 10-12 avenue de l'Europe, Vélizy, 78140 France
AB: The possibility of using fluid equations in collisionless plasmas is revisited, and the conditions of validity of several possible closure equations are investigated. A new derivation of the well-known ``double-adiabatic'' Chew-Goldberger-Low (CGL) laws is first presented. These laws are shown to demand two different kinds of conditions for ensuring (1) particle gyrotropy and (2) adiabaticity. Both kinds of conditions are investigated in detail. The usual slow and large scales conditions (hereafter ``sls''), which are shown to be necessary for gyrotropy, are provided in a rigorous form. The role of the fundamental symmetries of the system, especially in the directions parallel and perpendicular to the magnetic field, is also emphasized for determining any ``fluid-type'' behavior of a collisionless magnetoplasma. More general closure equations are afterwards proposed, relaxing first the conditions for adiabaticity and then, more speculatively, the sls conditions for gyrotropy. The dependence of these new closure equations on the shape of the velocity distribution functions is discussed, the CGL case being singular since it is shown to be fully independent of this shape.
DE: 2199 General or miscellaneous
DE: 2499 General or miscellaneous
DE: 2799 General or miscellaneous
DE: 5737 Magnetospheres (2756)
DE: 7899 General or miscellaneous
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005