Launching of accretion disc winds along dynamo-generated magnetic fields |
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| Authors: | C G Campbell |
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| Institution: | Department of Mathematics, University of Newcastle upon Tyne, Newcastle NE1 7RU |
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| Abstract: | The problem of magnetic field generation and advection in accretion discs is considered, in the context of wind launching and angular momentum extraction. A dipole-symmetry solution of the dynamo equations is found, with force-free boundary conditions appropriate for matching to a wind solution. Consideration of the curved field geometry and diffusive nature of the disc enables the position of the sonic point to be calculated and related to the field inclination at the disc surface. A critical inclination of 20° to the horizontal results, for which the sonic point lies in the disc surface and there is no potential barrier to wind launching. Hence the wind mass-loss rate will only become excessive, leading to disc disruption, for large field bending. The compressional effect of the horizontal magnetic field enhances the wind mass flux. |
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| Keywords: | accretion accretion discs magnetic fields |
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