| Name: Bidya Binay Karak |
| Affiliation: Indian Institute of Technology (BHU) Varanasi |
| Conference ID: ASI2026_157 |
| Title: Bipolar magnetic regions and their tilts: Implications for the solar dynamo and cycle variability |
| Abstract Type: Oral |
| Abstract Category: Sun, Solar System, Exoplanets, and Astrobiology |
| Author(s) and Co-Author(s) with Affiliation: Bidya Binay Karak(Department of Physics, Indian Institute of Technology (BHU), Varanasi 221005, India), Anu Sreedevi(Department of Physics, Indian Institute of Technology (BHU), Varanasi 221005, India) |
| Abstract: The solar convection zone is characterised by the birth of the concentrated magnetic field regions known as sunspots or, more generally, Bipolar Magnetic Regions (BMRs), which are tilted with respect to the equatorial line. Due to this tilt, when sunspots decay, they generate a poloidal field, which forms the seed for the sunspots for the next cycle. We shall present our observational efforts to identify the cause of the sunspot tilts. We analyse the tilt evolution of sunspots, starting from their appearance on the solar surface in the space-based magnetogram data over the last two solar cycles. We observe that from their appearance, BMRs exhibit tilts that are consistent with Joy’s law. This early tilt signature of BMRs suggests that the tilt is developed underneath the photosphere, driven by the Coriolis force, as predicted by the thin flux tube model. We further study the tilt angle properties of the ephemeral regions and tiny BMRs. Next, we illustrate the mechanism behind the variations in the solar cycle due to the variations in the sunspot properties. We shall show that tilt, flux, and time delay all have variations as given by their distributions, and these variations cause variations in the solar cycle, including short-and long-term variations in the solar cycle. |
