The solar dynamo: inferences from observations and modeling
arXiv:1404.4126 · doi:10.1134/S0016793214070056
Abstract
It can be shown on observational grounds that two basic effects of dynamo theory for solar activity - production of the toroidal field from the poloidal one by differential rotation and reverse conversion of the toroidal field to the poloidal configuration by helical motions - are operating in the Sun. These two effects, however, do not suffice for constructing a realistic model for the solar dynamo. Only when a non-local version of the alpha-effect is applied, is downward diamagnetic pumping included and field advection by the equatorward meridional flow near the base of the convection zone allowed for, can the observed activity cycles be closely reproduced. Fluctuations in the alpha-effect can be estimated from sunspot data. Dynamo models with fluctuating parameters reproduce irregularities of solar cycles including the grand activity minima. The physics of parametric excitation of irregularities remains, however, to be understood.
21 page (one column), 9 figures, to apper in Geomagnetism & Aeronomy (a review)
References in corpus (26)
- Astrophysical magnetic fields and nonlinear dynamo theory
- Grand minima and maxima of solar activity: New observational constraints
- Detection of Equatorward Meridional Flow and Evidence of Double-Cell Meridional Circulation inside the Sun
- Can Superflares Occur on Our Sun?
- Solar activity forecast with a dynamo model
- Full--Sphere Simulations of a Circulation--Dominated Solar Dynamo: Exploring the Parity Issue
- Exploring the Physical Basis of Solar Cycle Predictions: Flux Transport Dynamics and Persistence of Memory in Advection versus Diffusion Dominated Solar Convection Zones
- Turbulent magnetic Prandtl number and magnetic diffusivity quenching from simulations
- Global helioseismic evidence for a deeply penetrating Solar meridional flow consisting of multiple flow cells
- Is a deep one-cell meridional circulation essential for the flux transport Solar Dynamo?
- The origin of grand minima in the sunspot cycle
- Differential rotation of main-sequence dwarfs and its dynamo-efficiency
- Turbulent magnetic pumping in a Babcock-Leighton solar dynamo model
- Solar Grand Minima and random fluctuations in dynamo parameters
- Solar parity issue with flux-transport dynamo
- Does the Babcock--Leighton Mechanism Operate on the Sun?
- On the Amplitude of Convective Velocities in the Deep Solar Interior
- Grand Minima and North-South Asymmetry of Solar Activity
- Fluctuations in the Alpha-Effect and Grand Solar Minima
- Solar Dynamo Model with Diamagnetic Pumping and Nonlocal Alpha-Effect
- Magnetic helicity effects in astrophysical and laboratory dynamos
- Alpha effect due to buoyancy instability of a magnetic layer
- Diamagnetic pumping near the base of a stellar convection zone
- Magnetic buoyancy instabilities in the presence of magnetic flux pumping at the base of the solar convection zone
- Alleviation of catastrophic quenching in solar dynamo model with nonlocal alpha-effect
- Resonances for activity waves in spherical mean field dynamos