Magnetic Fields in the Solar Convection Zone

By Yuhong Fan. 2004

165 citations recorded by the source corpus.

AbstractRecent studies of the dynamic evolution of magnetic flux tubes in the solar convection zone are reviewed with focus on emerging flux tubes responsible for the formation of solar active regions. The current prevailing picture is that active regions on the solar surface originate from strong toroidal magnetic fields generated by the solar dynamo mechanism at the thin tachocline layer at the base of the solar convection zone. Thus the magnetic fields need to traverse the entire convection zone before they reach the photosphere to form the observed solar active regions. This review discusses results with regard to the following major topics: 1.the equilibrium properties of the toroidal magnetic fields stored in the stable overshoot region at the base of the convection zone,2.the buoyancy instability associated with the toroidal magnetic fields and the formation of buoyant magnetic flux tubes,3.the rise of emerging flux loops through the solar convective envelope as modeled by the thin flux tube calculations which infer that the field strength of the toroidal magnetic fields at the base of the solar convection zone is significantly higher than the value in equipartition with convection,4.the observed hemispheric trend of the twist of the magnetic field in solar active regions and its origin,5.the minimum twist needed for maintaining cohesion of the rising flux tubes,6.the rise of highly twisted kink unstable flux tubes as a possible origin of δ-sunspots,7.the evolution of buoyant magnetic flux tubes in 3D stratified convection,8.turbulent pumping of magnetic flux by penetrative compressible convection,9.an alternative mechanism for intensifying toroidal magnetic fields to significantly super-equipartition field strengths by conversion of the potential energy associated with the superadiabatic stratification of the solar convection zone, and finally10.a brief overview of our current understanding of flux emergence at the surface and post-emergence evolution of the subsurface magnetic fields.

Subfields: Astronomy and Astrophysics, Molecular Biology

View Paper: https://www.semanticscholar.org/paper/1ae9825f0f0bae578d54840ebd494dc6f6068365

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Citations in the corpus

Global-Scale Turbulent Convection and Magnetic Dynamo Action in the Solar Envelope (2004, background): “Alternatively, the patterns may arise from the action of Coriolis forces as flux tubes rise through the convection zone or from footpoint motions after they have emerged (e.g. Pevtsov 2002; Fan 2004).”
Dynamo Models of the Solar Cycle (2005, background): “…overshoot layer conjectured to exist immediately beneath the core-envelope interface (see, e.g., Schüssler, 1996; Schüssler and Ferriz-Mas, 2003; Fan, 2004, and references therein), Only there are growth rates for the magnetic buoyancy instability sufficiently long to allow field…”
SIMULATION OF THE FORMATION OF A SOLAR ACTIVE REGION (2010, unknown): “For a historical perspective of such work, the reader is referred to the review articles by Moreno-Insertis (1997), Fisher et al. (2000) and Fan (2004, 2009).”
Magnetic Flux Transport at the Solar Surface (2014, unknown): “See Fan (2009) for a review.”
Dynamo Action in the Solar Convection Zone and Tachocline: Pumping and Organization of Toroidal Fields (2006, background): “…the elements have now begun to be studied singly with reasonable fidelity using three-dimensional numerical modeling, often turning to localized planar domains to obtain sufficient spatial resolution within the simulations (see reviews by Ossendrijver 2003; Fan 2004; Charbonneau 2005; Miesch 2005).”
Driving major solar flares and eruptions: A review (2008, background): “…side, a persistent problem is that even state-of-the-art numerical experiments still have difficulty in successfully bringing flux bundles from some depth up into the photosphere without them exploding in the strongly stratified uppermost layers of the convective envelope (e.g., Fan 2004).”
Solar change and climate: an update in the light of the current exceptional solar minimum (2010, background): “But, magnetic ﬁelds cannot reside long in the CZ as their buoyancy makes them inherently unstable and they rapidly rise to the surface (see review by Fan 2004).”