Modeling sunspot and starspot decay by turbulent erosion
Litvinenko, Y. E., & Wheatland, M. S. (2015). Modeling sunspot and starspot decay by turbulent erosion. Astrophysical Journal, 800(2). http://doi.org/10.1088/0004-637X/800/2/130
Permanent Research Commons link: https://hdl.handle.net/10289/9309
Disintegration of sunspots (and starspots) by fluxtube erosion, originally proposed by Simon and Leighton, is considered. A moving boundary problem is formulated for a nonlinear diffusion equation that describes the sunspot magnetic field profile. Explicit expressions for the sunspot decay rate and lifetime by turbulent erosion are derived analytically and verified numerically. A parabolic decay law for the sunspot area is obtained. For moderate sunspot magnetic field strengths, the predicted decay rate agrees with the results obtained by Petrovay and Moreno-Insertis. The new analytical and numerical solutions significantly improve the quantitative description of sunspot and starspot decay by turbulent erosion.
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