Nonlinear Solar Dynamo Model with Magnetic Helicity

Abstract

Variations of the sunspot number are important indicators of the solar activity cycles. The sunspot formation is a result of a dynamo process inside the Sun, which is far from being understood. We use simple dynamical models of the dynamo process to simulate the magnetic field evolution and investigate general properties of the sunspot number variations during the solar cycles. We have found that the classical Parker's model with a standard kinetic helicity quenching cannot represent the typical profiles of the solar-cycle variations of the sunspot number, and also does not give chaotic solutions. For modeling of the solar cycle properties we use a nonlinear dynamo model of Kleeorin and Ruzmaikin (1982), which takes into account dynamics of the turbulent magnetic helicity. We have obtained a series of periodic and chaotic solutions for different layers of the convective zone. The solutions qualitatively reproduce some basic observational features of the solar cycle properties, in particular, the relationship between the growth time and the cycle amplitude. Also, on the longer time scale the dynamo model with the magnetic helicity has intermittent solutions, which may be important for modeling long-term variations of the solar cycles.

14 pages, 10 figures, published in Geophysical and Astrophysical Fluid Dynamics

References in corpus (8)

• Astrophysical magnetic fields and nonlinear dynamo theory
• Doubly Helical Coronal Ejections from Dynamos and their Role in Sustaining the Solar Cycle
• Galactic dynamos supported by magnetic helicity fluxes
• Magnetic Helicity Evolution During the Solar Activity Cycle: Observations and Dynamo Theory
• The Radial Distribution of Magnetic Helicity in the Solar Convective Zone: Observations and Dynamo Theory
• Helicity Balance and Steady-State Strength of the Dynamo Generated Galactic Magnetic Field
• Dynamos with different formulations of a dynamic alpha-effect
• New mechanism of generation of large-scale magnetic field in a sheared turbulent plasma

Cited by in corpus (8)

• Solar cycle prediction
• Solar Cycle Prediction
• The asymmetry of sunspot cycles and Waldmeier relations as due to nonlinear surface-shear shaped dynamo
• Application of Synoptic Magnetograms to Global Solar Activity Forecast
• 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
• Effects of Observational Data Shortage on Accuracy of Global Solar Activity Forecast
• Global Evolution of Solar Magnetic Fields and Prediction of Activity Cycles