Research Commons
      • Browse 
        • Communities & Collections
        • Titles
        • Authors
        • By Issue Date
        • Subjects
        • Types
        • Series
      • Help 
        • About
        • Collection Policy
        • OA Mandate Guidelines
        • Guidelines FAQ
        • Contact Us
      • My Account 
        • Sign In
        • Register
      View Item 
      •   Research Commons
      • University of Waikato Research
      • Computing and Mathematical Sciences
      • Computing and Mathematical Sciences Papers
      • View Item
      •   Research Commons
      • University of Waikato Research
      • Computing and Mathematical Sciences
      • Computing and Mathematical Sciences Papers
      • View Item
      JavaScript is disabled for your browser. Some features of this site may not work without it.

      Sunspot and Starspot lifetimes in a turbulent erosion model

      Litvinenko, Yuri E.; Wheatland, M.S.
      Thumbnail
      Files
      apj17_1.pdf
      Published version, 387.8Kb
      DOI
       10.3847/1538-4357/834/2/108
      Find in your library  
      Citation
      Export citation
      Litvinenko, Y. E., & Wheatland, M. S. (2017). Sunspot and Starspot lifetimes in a turbulent erosion model. Astrophysical Journal, 834(2). https://doi.org/10.3847/1538-4357/834/2/108
      Permanent Research Commons link: https://hdl.handle.net/10289/11065
      Abstract
      Quantitative models of sunspot and starspot decay predict the timescale of magnetic diffusion and may yield important constraints in stellar dynamo models. Motivated by recent measurements of starspot lifetimes, we investigate the disintegration of a magnetic flux tube by nonlinear diffusion. Previous theoretical studies are extended by considering two physically motivated functional forms for the nonlinear diffusion coefficient D: an inverse power-law dependence D ∝ B⁻ᵛ and a step-function dependence of D on the magnetic field magnitude B. Analytical self-similar solutions are presented for the power-law case, including solutions exhibiting "superfast" diffusion. For the step-function case, the heat-balance integral method yields approximate solutions, valid for moderately suppressed diffusion in the spot. The accuracy of the resulting solutions is confirmed numerically, using a method which provides an accurate description of long-time evolution by imposing boundary conditions at infinite distance from the spot. The new models may allow insight into the differences and similarities between sunspots and starspots.
      Date
      2017
      Type
      Journal Article
      Rights
      © 2017 The American Astronomical Society.
      Collections
      • Computing and Mathematical Sciences Papers [1455]
      Show full item record  

      Usage

      Downloads, last 12 months
      87
       
       
       

      Usage Statistics

      For this itemFor all of Research Commons

      The University of Waikato - Te Whare Wānanga o WaikatoFeedback and RequestsCopyright and Legal Statement