The basic concepts underlying our current understanding of solar and stellar magnetic activity cycles as being due to an internal dynamo process were laid out in more or less their current form some 70 years ago. Yet, at this writing, there exist no concensus "dynamo model of the solar cycle"; be it at the level of the relative importance of various potential inductive processes, of the...
The solar magnetic cycle is crucial for understanding solar activity and space weather. Two key models for studying it are the Surface Flux Transport (SFT) model and the 3D Babcock-Leighton dynamo model, respectively. The SFT model examines large-scale magnetic field evolution on the Sun's surface to predict solar cycles. In contrast, the 3D Babcock-Leighton model explores internal processes...
The 11-year sunspot cycles undergo amplitude modulation over longer timescales. As a part of this long-term modulation in solar activity, the decennial rhythm occasionally breaks, and sunspots disappear from the solar surface for multiple decades, leading to a period of magnetic quiescence on the Sun – known as the solar grand minimum. Observation of solar magnetic activity proxies suggest...
I describe some of the defining observations of the solar cycle that provide insights into the dynamo process, including the basics such as Hale and Joy's law, the spatio-temporal emergence of active regions that creates the butterfly diagram, and large-scale flows including zonal, meridional, etc. I also discuss new research on activity nests and active region flux emergence patterns....
In the solar atmosphere, active regions are dominated by the magnetic field, its complex topology and evolution. To understand the divers nature of active regions, we study a large sample of 3D magnetic field configurations to derive general properties relating magnetic flux, magnetic energy and magnetic field scale-height. We compute the magnetic fields under the potential field assumption...
