04/29/02
Grappin roland	observatoire de Meudon
1 pl Janssen	PNST-
92195	Meudon, France

Presentation 1 : Oral
Chaotic siphon flows in coronal loops driven by Alfv\'en waves (PNST)
R. Grappin, J. Leorat, L. Ofman
We consider a 1.5 D model of a coronal loop excited by Alfv\'en waves, with open boundary conditions. The wave injection induces quasi-periodic oscillations of the thermal pressure at the two loop boundaries, which in turn leads to chaotic flows, oscillating between subsonic and transonic, or permanently transonic, with a randomly fluctuating transonic point. The relevant parameters and their effect on the flow regime are discussed.
Presentation 2 : Oral
Coronal response to wave excitation in open and closed magnetic field
R. Grappin, J. Leorat, S. Habbal
We consider a 2.5D (axisymmetric) model of the solar wind with Alfv\'en waves injected at the coronal base. One discusses the different flow regimes induced by the wave excitation, and the coupling between open and closed regions.

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