Is hemispheric asymmetry in the sunspot cycle solely governed by polar flux imbalance in the previous cycle?

Prantika Bhowmik

Published 2019-06-17Version 1

Hemispheric irregularities of solar magnetic activity is a well-observed phenomenon -- the origin of which has been studied through numerical simulations and data-analysis techniques. In this work we explore possible causes generating north-south asymmetry in the reversal timing and the amplitude of polar field during cycle minimum. Additionally, we investigate how hemispheric asymmetry is translated from cycle to cycle. We pursue a three-step approach. Firstly, we explore the asymmetry present in the observed polar flux and sunspot area by analyzing observational data of the last 110 years. Secondly, we investigate contribution from different factors involved in the Babcock-Leighton mechanism to the evolution and generation of polar flux by performing numerical simulations with a Surface Flux Transport model and synthetic sunspot input profiles. Thirdly, propagation of hemispheric asymmetry in the following cycle is estimated by assimilating simulation-generated surface magnetic field maps at cycle minimum in a dynamo simulation. Finally, we assess our understanding of hemispheric asymmetry while reproducing observed asymmetry in the eight past solar cycles by performing additional observational data-driven simulations.