AAS 199th meeting, Washington, DC, January 2002
Session 132. AGN - Modeling
Display, Thursday, January 10, 2002, 9:20am-4:00pm, Exhibit Hall

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[132.03] The Effect of MHD Winds on Trans-Alfvénic Jets

P.E. Hardee (U. Alabama), A. Rosen (Armagh Obs.)

Jets in protostellar systems and jets in AGN may be surrounded by a more slowly moving magnetized wind. Theoretical analysis and numerical simulations of 3D MHD jets reveal that destabilization of these jets by the Kelvin-Helmholtz instability can be delayed considerably by the presence of a relatively modest magnetized wind flow outside the more highly collimated jet flow. In the absence of a wind a ``light'' jet destabilizes abruptly to helical and other non-axisymmetric modes of distortion at the Alfvén point transition from sub- to super-Alfvénic flow. The wind flow can stabilize or significantly reduce the growth rate of non-axisymmetric jet distortion to locations well beyond the Alfvén point. The unstable axisymmetric pinch mode distortion remains much less influenced by an external wind and can be the dominant unstable mode. Thus, we find a mechanism that could produce knots in the flow without accompanying destructive non-axisymmetric jet distortions.

Supported by the National Science Foundation through grant AST-9802955 to the University of Alabama.

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