• Login
    • Submit
    View Item 
    •   Repository Home
    • UT Faculty/Researcher Works
    • UT Faculty/Researcher Works
    • View Item
    • Repository Home
    • UT Faculty/Researcher Works
    • UT Faculty/Researcher Works
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    The Role Of The Magnetorotational Instability In The Sun

    Icon
    View/Open
    2014_05_magnetorotational.pdf (1.308Mb)
    Date
    2014-05
    Author
    Kagan, Daniel
    Wheeler, J. Craig
    Share
     Facebook
     Twitter
     LinkedIn
    Metadata
    Show full item record
    Abstract
    We calculate growth rates for nonaxisymmetric instabilities including the magnetorotational instability (MRI) throughout the Sun. We first derive a dispersion relation for nonaxisymmetric instability including the effects of shear, convective buoyancy, and three diffusivities (thermal conductivity, resistivity, and viscosity). We then use a solar model evolved with the stellar evolution code MESA and angular velocity profiles determined by Global Oscillations Network Group helioseismology to determine the unstable modes present at each location in the Sun and the associated growth rates. The overall instability has unstable modes throughout the convection zone and also slightly below it at middle and high latitudes. It contains three classes of modes: large-scale hydrodynamic convective modes, large-scale hydrodynamic shear modes, and small-scale magnetohydrodynamic shear modes, which may be properly called MRI modes. While large-scale convective modes are the most rapidly growing modes in most of the convective zone, MRI modes are important in both stably stratified and convectively unstable locations near the tachocline at colatitudes theta < 53 degrees. Nonaxisymmetric MRI modes grow faster than the corresponding axisymmetric modes; for some poloidal magnetic fields, the nonaxisymmetric MRI growth rates are similar to the angular rotation frequency Omega, while axisymmetric modes are stabilized. We briefly discuss the saturation of the field produced by MRI modes, finding that the implied field at the base of the convective zone in the Sun is comparable to that derived based on dynamos active in the tachocline and that the saturation of field resulting from the MRI may be of importance even in the upper convection zone.
    Department
    Astronomy
    Subject
    instabilities
    magnetohydrodynamics (mhd)
    stars: magnetic field
    stars:
    rotation
    sun: rotation
    solar convection-zone
    latitudinal differential rotation
    toroidal
    magnetic-fields
    proto-neutron stars
    adiabatic stability
    dynamo
    tachocline
    interior
    surface
    disks
    astronomy & astrophysics
    URI
    http://hdl.handle.net/2152/34694
    Citation
    Kagan, Daniel, and J. Craig Wheeler. "The role of the magnetorotational instability in the Sun." The Astrophysical Journal, Vol. 787, No. 1 (May., 2014): 21.
    Collections
    • UT Faculty/Researcher Works
    University of Texas at Austin Libraries
    • facebook
    • twitter
    • instagram
    • youtube
    • CONTACT US
    • MAPS & DIRECTIONS
    • JOB OPPORTUNITIES
    • UT Austin Home
    • Emergency Information
    • Site Policies
    • Web Accessibility Policy
    • Web Privacy Policy
    • Adobe Reader
    Subscribe to our NewsletterGive to the Libraries

    © The University of Texas at Austin

    Browse

    Entire RepositoryCommunities & CollectionsDate IssuedAuthorsTitlesSubjectsDepartmentThis CollectionDate IssuedAuthorsTitlesSubjectsDepartment

    My Account

    Login

    Information

    AboutContactPoliciesGetting StartedGlossaryHelpFAQs

    Statistics

    View Usage Statistics
    University of Texas at Austin Libraries
    • facebook
    • twitter
    • instagram
    • youtube
    • CONTACT US
    • MAPS & DIRECTIONS
    • JOB OPPORTUNITIES
    • UT Austin Home
    • Emergency Information
    • Site Policies
    • Web Accessibility Policy
    • Web Privacy Policy
    • Adobe Reader
    Subscribe to our NewsletterGive to the Libraries

    © The University of Texas at Austin