Babcock Redux: An Ammendment of Babcock's Schematic of the Sun's Magnetic Cycle

TL;DR

This paper proposes an improved model of the Sun's magnetic cycle that aligns with recent observations, emphasizing the role of magnetic flux tubes, topological pumping, and differential rotation in the dynamo process.

Contribution

It introduces a revised schematic of the solar magnetic cycle incorporating flux tube dynamics and convection zone processes, enhancing Babcock's original model.

Findings

The amended scenario fits observed magnetic activity features.

It emphasizes the role of flux tubes and topological pumping.

It suggests the model's viability can be tested with flux-transport simulations.

Abstract

We amend Babcock's original scenario for the global dynamo process that sustains the Sun's 22-year magnetic cycle. The amended scenario fits post-Babcock observed features of the magnetic activity cycle and convection zone, and is based on ideas of Spruit and Roberts (1983) about magnetic flux tubes in the convection zone. A sequence of four schematic cartoons lays out the proposed evolution of the global configuration of the magnetic field above, in, and at the bottom of the convection zone through sunspot Cycle 23 and into Cycle 24. Three key elements of the amended scenario are: (1) as the net following-polarity field from the sunspot-region omega-loop fields of an ongoing sunspot cycle is swept poleward to cancel and replace the opposite-polarity polar-cap field from the previous sunspot cycle, it remains connected to the ongoing sunspot cycle's toroidal source-field band at the bottom of the convection zone; (2) topological pumping by the convection zone's free convection keeps the horizontal extent of the poleward-migrating following-polarity field pushed to the bottom, forcing it to gradually cancel and replace old horizontal field below it that connects the ongoing-cycle source-field band to the previous-cycle polar-cap field; (3) in each polar hemisphere, by continually shearing the poloidal component of the settling new horizontal field, the latitudinal differential rotation low in the convection zone generates the next-cycle source-field band poleward of the ongoing-cycle band. The amended scenario is a more-plausible version of Babcock's scenario, and its viability can be explored by appropriate kinematic flux-transport solar-dynamo simulations.