The asymmetry of sunspot cycles and Waldmeier relations as due to nonlinear surface-shear shaped dynamo

Abstract

The paper presents a study of a solar dynamo model operating in the bulk of the convection zone with the toroidal magnetic field flux concentrated in the subsurface rotational shear layer. We explore how this type of dynamo may depend on spatial variations of turbulent parameters and on the differential rotation near the surface. The mean-field dynamo model takes into account the evolution of magnetic helicity and describes its nonlinear feedback on the generation of large-scale magnetic field by the $\alpha$-effect. We compare the magnetic cycle characteristics predicted by the model, including the cycle asymmetry (associated with the growth and decay times) and the duration - amplitude relation (Waldmeier's effects), with the observed sunspot cycle properties. We show that the model qualitatively reproduces the basic properties of the solar cycles.

28 pages, 7 figures(Second revision, figures updates)

References in corpus (7)

• The case for a distributed solar dynamo shaped by near-surface shear
• The subsurface-shear shaped solar $\alpha \Omega$ dynamo
• The mean electro-motive force, current- and cross-helicity under the influence of rotation, magnetic field and shear
• Study of isotopic fractions and abundances of the neutron-capture elements in HD 175305
• Nonlinear Solar Dynamo Model with Magnetic Helicity
• Shear-driven and diffusive helicity fluxes in alpha-Omega dynamos
• Alleviating alpha quenching by solar wind and meridional flow

Cited by in corpus (31)

• Solar cycle prediction
• H-alpha Activity of Old M Dwarfs: Stellar Cycles and Mean Activity Levels For 93 Low-Mass Stars in the Solar Neighborhood
• Cross helicity and related dynamo
• On the role of tachoclines in solar and stellar dynamos
• The quasi-biennial periodicity as a window on the solar magnetic dynamo configuration
• Variations of the solar cycle profile in a solar dynamo with fluctuating dynamo governing parameters
• The mean-field solar dynamo with double cell meridional circulation pattern
• On the Origin of Solar Torsional Oscillations and Extended Solar Cycle
• Physical link of the polar field build-up with the Waldmeier effect broadens the scope of early solar cycle prediction: Cycle 25 is likely to be slightly stronger than Cycle 24
• The origin of the helicity hemispheric sign rule reversals in the mean-field solar-type dynamo
• Waldmeier Effect in Stellar Cycles
• Spectral characteristic of mid-term quasi-periodicities in sunspots data
• Helicity conservation in nonlinear mean-field solar dynamo
• Does the mean-field alpha effect have any impact on the memory of the solar cycle?
• Effects of Emerging Bipolar Magnetic Regions in Mean-field Dynamo Model of Solar Cycles 23 and 24
• Dependence of magnetic cycle parameters on period of rotation in nonlinear solar-type dynamos
• Effects of anisotropy of turbulent convection in mean-field solar dynamo models
• Nonkinematic solar dynamo models with double-cell meridional circulation
• Dependence of stellar magnetic activity cycles on rotational period in nonlinear solar-type dynamo
• The fluctuating α-effect and Waldmeier relations in the nonlinear dynamo models
• Reversals of the solar magnetic dipole in the light of observational data and simple dynamo models
• A new simple dynamo model for stellar activity cycle
• Solar differential rotation: hints to reproduce a near-surface shear layer in global simulations
• Mapping the Cosmic Web with the largest all-sky surveys
• Helicity-vorticity turbulent pumping of magnetic fields in solar convection zone
• Effects of Observational Data Shortage on Accuracy of Global Solar Activity Forecast
• Advances in mean-field dynamo theories
• Waldmeier relations and the solar cycle dynamics by the mean-field dynamos
• Is meridional circulation important in modelling irregularities of the solar cycle?
• Solar cycle asymmetry as a consequence of fluctuations in dynamo parameters
• Calibration of the Sunspot and Group Numbers Using the Waldmeier Effect