Séminaire / Seminar GReCO |
| « Multi-Fluids and the Two-Stream Instability » |
|
G. L. Comer |
| The two-stream instability is a generic mechanism requiring at least two interacting fluids that can exhibit relative flow. Any disturbance that looks to be forward moving with respect to one fluid, but backward with respect to the other, is subject to instability. The relative flow can be along an interface, such as the atmosphere across the oceans, or through interpenetrating fluids, like plasmas, superfluid helium four, or even the interiors of neutron stars. We discuss first a Newtonian multi-fluid formalism due primarily to Carter, Langlois, Prix and their collaborators. We then apply this formalism to the case of two interpenetrating fluids and establish the existence of the two-stream instability. In principle, such an instability could be found in laboratory superfluid helium, where one fluid is the mass current and the other is the entropy flow, or in the inner crusts and outer cores of neutron stars, with one fluid being superfluid neutrons and the other consisting of the charged constituents (crust nuclei, superconducting protons, electrons, and perhaps even muons). |
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jeudi 25 novembre 2004 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |