Collimation of magnetically driven jets from accretion discs
نویسندگان
چکیده
منابع مشابه
Magnetically-driven jets from Keplerian accretion discs
Non-relativistic, magnetically-driven jets are constructed by taking self-consistently into account the feedback on the underlying accretion disc. It is shown that such jets are mostly described by the ejection index ξ = d ln Ṁa/d ln r, which is a local measure of the disc ejection efficiency. This parameter is found to lie in a very narrow range, due to constraints imposed by both the disc ver...
متن کاملStability and heating of magnetically driven jets from Keplerian accretion discs
We have performed 3-D numerical magnetohydrodynamic (MHD) jet experiments to study the instabilities associated with strongly toroidal magnetic fields. In contemporary jet theories, a highly wound up magnetic field is a crucial ingredient for collimation of the flow. If such magnetic configurations are as unstable as found in the laboratory and by analytical estimates, our understanding of MHD ...
متن کاملMagnetized accretion-ejection structures IV. Magnetically-driven jets from resistive, viscous, Keplerian discs
We present steady-state calculations of self-similar magnetized accretion discs driving cold, adiabatic, non-relativistic jets. For the first time, both the magnetic torque due to the jets and a turbulent “viscous” torque are taken into account. This latter torque allows a dissipation of the accretion power as radiation at the disc surfaces, while the former predominantly provides jets with pow...
متن کاملEpisodic accretion in magnetically layered protoplanetary discs
We study protoplanetary disc evolution assuming that angular momentum transport is driven by gravitational instability at large radii, and magnetohydrodynamic (MHD) turbulence in the hot inner regions. At radii of the order of 1 AU such discs develop a magnetically layered structure, with accretion occurring in an ionized surface layer overlying quiescent gas that is too cool to sustain MHD tur...
متن کاملTheory of magnetized accretion discs driving jets
In this lecture I review the theory of magnetized accretion discs driving jets, with a focus on Young Stellar Objects (YSOs). I first introduce observational and theoretical arguments in favor of the “disc wind” paradigm. There, accretion and ejection are interdependent, requiring therefore to revisit the standard picture of accretion discs. A simple magnetostatic approach is shown to already p...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1997
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/288.2.333