Dynamo action by differential rotation in a stably stratified stellar interior

By H. Spruit. 2001

772 citations recorded by the source corpus.

Magnetic fields can be created in stably stratified (non-convective) layers in a differentially rotating star. A magnetic instability in the toroidal field (wound up by differential rotation) replaces the role of convection in closing the field amplification loop. Tayler instability is likely to be the most relevant magnetic instability. A dynamo model is developed from these ingredients, and applied to the problem of angular momentum transport in stellar interiors. It produces a predominantly horizontal field. This dynamo process is found to be more effective in transporting angular momentum than the known hydrodynamic mechanisms. It might account for the observed pattern of rotation in the solar core.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/ee57099edbc3c2fead8bc2332fea79460466889c

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Citations in the corpus

• The Rates of Hypernovae and Gamma-Ray Bursts: Implications for Their Progenitors (2004, background): “However, there are many well-established mechanisms by which they can lose their angular momentum during their evolution by both hydrodynamical (e.g. winds) and magnetohydrodynamical processes (Spruit & Phinney 1998; Spruit 2002).”
• Evolutionary roads leading to low effective spins, high black hole masses, and O1/O2 rates for LIGO/Virgo binary black holes (2017, methodology): “…momentum transport of the magnetic dynamo (νST ∼ −( d ln Ωd ln r )2) in a region where stratification is dominated by the chemical composition gradient (Spruit 2002), which is the case for the region above the helium core where the shear develops after the MS evolution in a massive star,…”
• Presupernova Evolution of Differentially Rotating Massive Stars Including Magnetic Fields (2004, methodology): “This way the discussion in Spruit (2002) can be followed without further revision.”
• The VLT FLAMES Survey of Massive Stars: Rotation and Nitrogen Enrichment as the Key to Understanding Massive Star Evolution (2007, methodology): “…updated the mass-loss prescription and now use the recipe of Vink et al. (2001) and we disregard the magnetically induced chemical diffusion term of Spruit (2002), which—in contrast to the magnetic angular momentum transport—is not observationally supported, and appears controversial at present…”
• Binary Black Hole Population Properties Inferred from the First and Second Observing Runs of Advanced LIGO and Advanced Virgo (2018, background): “…transfer(Packet 1981; Shu & Lubow 1981) and tidal interactions(Petrovic et al. 2005), as well as internal mixing of the stellar layers across the core-envelope boundary via magnetic torquing(Spruit 2002; Maeder & Meynet 2003) and gravity waves(Talon & Charbonnel 2005, 2008; Fuller et al. 2015).”
• Slowing the spins of stellar cores (2019, methodology): “Spruit (2002) considered the limit of pure thermal/compositional stratification, but in red giant cores, both components are important.”
• Explosion mechanism, neutrino burst and gravitational wave in core-collapse supernovae (2005, background): “effect of toroidal magnetic fields While most of the magnetohydrodynamic (MHD) simulations in the context of core-collapse supernovae choose poloidal magnetic fields as initial conditions [217, 40, 274, 265, 306, 12, 405], recent stellar evolution calculations show that toroidal magnetic fields may ”
• The Progenitor Stars of Gamma-Ray Bursts (2005, methodology): “In Heger et al. (2005), we showed that current estimates of magnetic torques in the interiors of evolving massive stars (Spruit 2002) led naturally to rotation rates of pulsars in the range 10 -15 ms, just what was needed.”
• SUPERNOVA LIGHT CURVES POWERED BY FALLBACK ACCRETION (2012, background): “Stellar cores spin up as they contract, and depending on the efficiency of angular momentum transfer from magnetic torques (Spruit 2002) can transfer much of the core angular momentum to the outer layers (e.g., Heger et al. 2005).”
• Stellar evolution with rotation and magnetic fields III. The interplay of circulation and dynamo (2005, methodology): “The interpolation was made by Spruit (2002) as a function of the parameter q, which defines the amount of differential rotation (see definition given in Eq.”
• Stellar evolution with rotation - XIII. Predicted GRB rates at various Z (2005, background): “Petrovic et al. (2005) find, including the effects of magnetic fields according to Spruit (2002) that, neither the single nor the binary star models that they calculated retain enough angular momentum to form GRBs. Finally, magnetic braking, which is implemented mainly to reproduce the observed…”
• Rotational mixing in massive binaries - Detached short-period systems (2009, methodology): “We do not consider possible mixing by instabilities related to magnetic buoyancy due to winding up of the magnetic field lines through differential rotation (Spruit 2002) as this leads to too efficient mixing (Hunter et al. 2008).”
• ANGULAR MOMENTUM TRANSPORT WITHIN EVOLVED LOW-MASS STARS (2014, background): “The mixing of angular momentum due to dynamo-generated magnetic fields in radiative zones is also included (Spruit 2002; Petrovic et al. 2005; Heger et al. 2005).”
• THE LONG-TERM EVOLUTION OF DOUBLE WHITE DWARF MERGERS (2011, background): “…such as the magnetorotational instability (Balbus & Hawley 1991; Hawley & Balbus 1991; Balbus 2003) and the Tayler-Spruit dynamo (Tayler 1973; Spruit 1999, 2002) operate efficiently, angular momentum will be redistributed throughout the remnant much more rapidly than heat can be radiated…”
• GWTC-2.1: Deep extended catalog of compact binary coalescences observed by LIGO and Virgo during the first half of the third observing run (2021, positive): “01 ) for single BHs because of efficient angular momentum transport in the stellar interior [245].”
• Single star progenitors of long gamma-ray bursts - I. Model grids and redshift dependent GRB rate (2006, methodology): “To explore this uncertainty, we make simple experiments by introducing a free parameter fν,mag such that νmag = fν,mag · νST, (4) where νST is the magnetic viscosity according to Spruit (2002), and νmag is the magnetic viscosity used in the code.”
• Angular momentum transport by heat-driven g-modes in slowly pulsating B stars (2017, methodology): “The efficacy of the TS dynamo remains a topic of ongoing debate (see, e.g., Spruit 2002; Denissenkov & Pinsonneault 2007; Zahn et al. 2007), and we therefore perform two simulations: for our ‘magnetic’ simulation the dynamo is enabled in mesastar, and for the ‘non-magnetic’ one it is turned off.”