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Centro de Astrofísica da Universidade do Porto

Stellar Winds Models with Alfvén Waves

L. J. R. Machado, J. J. G. Lima, M. T. V. T. Lago

Abstract
It is known that stellar winds from late type stars are of mixed thermal and magnetic origin. The stellar wind model presented in this work uses the hydrodynamic equations of mass and momentum conservation and closes the system of equations with a detailed energy equation. Both momentum and energy equations have terms due to the effects of Alfvén waves. A smooth transition between the two regimes for Alfvén wave propagation, the undamped and the damped modes, is achieved by considering the geometrical mean of both wave amplitudes. It will be shown that the initial push on the plasma is provided by the mechanical heating input, and that further out the Alfvén waves take over energetically.

Astrophysics and Space Science
Volume 287, Page 139
March 2003

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