Physical Models for Solar Cycle Predictions

Abstract

The dynamic activity of stars such as the Sun influences (exo)planetary space environments through modulation of stellar radiation, plasma wind, particle and magnetic fluxes. Energetic stellar phenomena such as flares and coronal mass ejections act as transient perturbations giving rise to hazardous space weather. Magnetic fields -- the primary driver of stellar activity -- are created via a magnetohydrodynamic dynamo mechanism within stellar convection zones. The dynamo mechanism in our host star -- the Sun -- is manifest in the cyclic appearance of magnetized sunspots on the solar surface. While sunspots have been directly observed for over four centuries, and theories of the origin of solar-stellar magnetism have been explored for over half a century, the inability to converge on the exact mechanism(s) governing cycle to cycle fluctuations and inconsistent predictions for the strength of future sunspot cycles have been challenges for models of solar cycle forecasts. This review discusses observational constraints on the solar magnetic cycle with a focus on those relevant for cycle forecasting, elucidates recent physical insights which aid in understanding solar cycle variability, and presents advances in solar cycle predictions achieved via data-driven, physics-based models. The most successful prediction approaches support the Babcock-Leighton solar dynamo mechanism as the primary driver of solar cycle variability and reinforces the flux transport paradigm as a useful tool for modelling solar-stellar magnetism.

50 pages, 7 figures, submitted to Space Science Reviews

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• Solar activity forecast with a dynamo model
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• Predicting the Amplitude and Hemispheric Asymmetry of Solar Cycle 25 with Surface Flux Transport
• Solar Cycle Variability Induced by Tilt Angle Scatter in a Babcock--Leighton Solar Dynamo Model
• The Effect of "Rogue" Active Regions on the Solar Cycle
• Turbulent Pumping of Magnetic Flux Reduces Solar Cycle Memory and thus Impacts Predictability of the Sun's Activity
• Surface Flux Transport on the Sun
• Source of a Prominent Poleward Surge During Solar Cycle 24
• Helioseismic data inclusion in solar dynamo models
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Cited by in corpus (12)

• Impact of Anomalous Active Regions on the Large-scale Magnetic Field of the Sun
• Predicting the Timing of the the Solar Cycle 25 Polar Field Reversal
• Discovery of a relation between the decay rate of the Sun's magnetic dipole and the growth rate of the following sunspot cycle: a new precursor for solar cycle prediction
• Algebraic Quantification of the Contribution of Active Regions to the Sun's Dipole Moment: Applications to Century-scale Polar Field Estimates and Solar Cycle Forecasting
• Forecasting the solar cycle using variational data assimilation: validation on cycles 22 to 25
• On the origin of long-term modulation in the Sun's magnetic activity cycle
• Minimal Roles of Solar Subsurface Meridional Flow in the distributed-shear Babcock-Leighton Dynamo
• Hemispheric analysis of the magnetic flux in regular and irregular solar active regions
• Solar active region scaling laws revisited
• Effect of Nonlinear Surface Inflows into Activity Belts on Solar Cycle Modulation
• Solar Cycle Prediction: Challenges, Progress, and Future Perspectives
• Uncovering the Dominant Spatial Scales of the Sun's Magnetic Field in Solar Cycle 24