One obvious feature of the solar cycle is its variation from one cycle to another. In this article,
we review the dynamo models for the long-term variations of the solar cycle. By long-term …

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 …

Theoretical models for the solar dynamo range from simple low-dimensional “toy models” to
complex 3D-MHD simulations. Here we mainly discuss appproaches that are motivated and …

The prediction of the strength of an upcoming solar cycle has been a long-standing
challenge in the field of solar physics. The inherent stochastic nature of the underlying solar …

The polar field reversal is a crucial process in the cyclic evolution of the large-scale
magnetic field of the Sun. Various important characteristics of a solar cycle, such as its …

We describe the defining observations of the solar cycle that provide constraints for the
dynamo processes operating within the Sun. Specifically, we report on the following topics …

Magnetic activity is a ubiquitous feature of stars with convective outer layers, with
implications from stellar evolution to planetary atmospheres. Investigating the mechanisms …

We propose a self-consistent explanation of Rieger-type periodicities, the Schwabe cycle,
and the Suess-de Vries cycle of the solar dynamo in terms of resonances of various wave …

The Sun plays a role in influencing Earth's climate, making it important to have accurate
information about variations in the Sun's radiative output. Models are used to recover total …

Abstract The Committee on Space Research (COSPAR) is updating its Roadmap on Space
Weather. As input for this update, the COSPAR International Space Weather Action Teams …