Uniting The Sun's Hale Magnetic Cycle and `Extended Solar Cycle' Paradigms

TL;DR

This paper explores the relationship between the Hale magnetic cycle and the Extended Solar Cycle, emphasizing their connection through observational data and implications for solar activity prediction.

Contribution

It presents a detailed analysis linking the Hale cycle with the Extended Solar Cycle using observational data from the Wilcox Solar Observatory.

Findings

Correlation between Hale cycle and Extended Solar Cycle established

Surface magnetic field evolution aligns with Hale cycle phases

Implications for solar cycle prediction discussed

Abstract

Through meticulous daily observation of the Sun's large-scale magnetic field the Wilcox Solar Observatory (WSO) has catalogued two magnetic (Hale) cycles of solar activity. Those two (~22-year long) Hale cycles have yielded four ($\sim$11-year long) sunspot cycles (numbers 21 through 24). Recent research has highlighted the persistence of the "Extended Solar Cycle" (ESC) and its connection to the fundamental Hale Cycle - albeit through a host of proxies resulting from image analysis of the solar photosphere, chromosphere and corona. This short manuscript presents the correspondence of the ESC, the surface toroidal magnetic field evolution, and the evolution of the Hale Cycle. As Sunspot Cycle 25 begins, interest in observationally mapping the Hale and Extended cycles could not be higher given potential predictive capability that synoptic scale observations can provide.