title: Why does the sun's torsional oscillation begin before the sunspot cycle?
abstract: Although the Sun's torsional oscillation is believed to be driven by the Lorentz force associated with the sunspot cycle, this oscillation begins 2-3 yr before the sunspot cycle. We provide a theoretical explanation of this with the help of a solar dynamo model having a meridional circulation penetrating slightly below the bottom of the convection zone, because only in such dynamo models does the strong toroidal field form a few years before the sunspot cycle and at a higher latitude.
authors.affiliation: Department of Theoretical Sciences, S. N. Bose Centre for Basic Sciences, Kolkata-700098, India.
authors.forename: Sagar
authors.initials: S
authors.lastname: Chakraborty
authors.forename: Arnab Rai
authors.initials: AR
authors.lastname: Choudhuri
authors.forename: Piyali
authors.initials: P
authors.lastname: Chatterjee