2010/08/13 by Bidya Binay Karak, Arnab Rai Choudhuri · 2 citations
Engineering · Physics and Astronomy · #Cosmology and Gravitation Theories #Diffusion #Dynamo #Fluid dynamics and aerodynamics studies #Flux (metallurgy) #Magnetic flux #Magnetohydrodynamics #Meridional flow #Solar and Space Plasma Dynamics #Solar dynamo #Sunspot #Turbulence #astro-ph.EP #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.1111/j.1365-2966.2010.17531.x
published as Monthly Notices Roy. Astron. Soc. 410, 1503-1512 (2011) · Being reviewed in MNRAS
arxiv created 2010/08/13 · openalex publication_date 2010/10/01 · arxiv updated 2011/02/08 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We confirm that the evidence for the Waldmeier effect WE1 (the anticorrelation between rise times of sunspot cycles and their strengths) and the related effect WE2 (the correlation between rise rates of cycles and their strengths) is found in different kinds of sunspot data. We explore whether these effects can be explained theoretically on the basis of the flux transport dynamo models of sunspot cycles. Two sources of irregularities of sunspot cycles are included in our model: fluctuations in the poloidal field generation process and fluctuations in the meridional circulation. We find WE2 to be a robust result which is produced in different kinds of theoretical models for different sources of irregularities. The Waldmeier effect WE1, on the other hand, arises from fluctuations in the meridional circulation and is found only in the theoretical models with reasonably high turbulent diffusivity which ensures that the diffusion time is not more than a few years.