Abstract
The energetics of mixing material through a chemical composition gradient is considered. In regions where nuclear reactions are significant the rate of energy input required to maintain mixing against the growing composition gradient is of the order of the internal energy per nuclear time scale, this is greater than the rate of energy available from most sources except nuclear reactions themselves. Thus angular momentum transport by material motion is only likely to be effective in convective zones (and any associated overshoot regions), and possibly by instabilities themselves driven by nuclear reactions. Even though the angular velocity gradient may be unstable, transport of angular momentum by rotationally driven instabilities will be inhibited. Transport by magnetic fields does not require material motion through a composition gradient and is likely to be very effective in establishing almost uniform rotation. If the rotation is not constant then the differential rotation produces a toroidal field which reacts back on the differential rotation leading to torsional oscillations with a period of the local Alfven travel time. Neighbouring field lines rapidly get out of phase with each other creating a large gradient in magnetic field and substantial dissipation. This is likely to establish almost uniform rotation as this is the lowest energy state for a given angular momentum.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Biermann L 1950, Zeit fur Naturforschung A, 5, 65.
Christensen-Dalsgaard J, Dilke F W W and Gough D O, 1974, Monthly Notices Roy Astron Soc, 169, 429.
Dilke F W W and Gough D O 1972, Nature, 240, 262.
Fricke K 1968, Zeitschrift fur Astrophysik, 68, 317.
Goldreich P and Schubert G 1967. Astrophysical Journal, 150, 571.
Knoblock E and Spruit H 1983 Astronomy and Astrophysics, 125, 59.
Roxburgh I W 1966, “On Stellar Rotation III” Mon Not Roy Ast Soc, 132, 201.
Roxburgh I W, 1975, ‘The Bubble Derivation of the Thermal Stability Criteria for a Rotating Star’“, Memoires de la Societe Royale des Sciences de Liege, 6e serie, 8, 69.
Roxburgh I W 1984a, On Turbulent Mixing“, Observational Tests of the Stellar Evolution Theory, ed A Maeder and A Renzini, 519, D Reidel Pub Co., Dordrecht.
Roxburgh I W 1984b, Rotational Instabilities in the Solar Interior, Turbulent Diffusion and the Solar Neutrino Problem, Mem Soc Astro Ital. 55, 273.
Roxburgh I W 1984c, “The Stability of Differentially Rotating Stars”. paper dedicated to Paul Ledoux and presented at the 25th Liege Symposium, 1984.
Roxburgh I W 1985a, “Instabilities, Mixing and Solar Neutrinos”, Solar Neutrinos and Neutrino Astronomy, ed M L Cherry, W A Fowler and K Lande, Am Institute Physics, 88.
Roxburgh I W 1985b, “Present Problems of the Solar Interior”, Solar Physics, 100, 21.
Roxburgh I W 1987, “Problems of the Solar Interior”, in The Internal Solar Angular Velocity, ed B Durney and S Sofia. D Reidel Publishing Company, p 1.
Spruit H, Knoblock E and Roxburgh I W 1984, Nature, 304, 320.
Shibahashi H 1980, Publ Asrton Soc Japan, 22, 341.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1991 Springer Science+Business Media Dordrecht
About this chapter
Cite this chapter
Roxburgh, I.W. (1991). Angular Momentum Transport, Rotational Instabilities, Magnetic Fields and Mixing. In: Catalano, S., Stauffer, J.R. (eds) Angular Momentum Evolution of Young Stars. NATO ASI Series, vol 340. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-3580-1_32
Download citation
DOI: https://doi.org/10.1007/978-94-011-3580-1_32
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-010-5587-1
Online ISBN: 978-94-011-3580-1
eBook Packages: Springer Book Archive