Phase relationships of solar hemispheric toroidal and poloidal cycles

TL;DR

This study investigates the phase relationships between hemispheric solar activity cycles and magnetic field reversals, revealing a long-term pattern suggesting a component of the solar dynamo with long-term memory.

Contribution

It extends previous analysis of hemispheric phase lags to earlier solar cycles and links these lags with magnetic field reversals, indicating a long-term property of the solar dynamo mechanism.

Findings

Hemispheric phase lags show a pattern of exchange every four cycles.

Magnetic field reversal lags follow the same long-term variation.

The variation suggests a long-term memory component in the solar dynamo.

Abstract

The solar northern and southern hemispheres exhibit differences between the intensities and time profiles of the activity cycles. The time variation of these properties has been studied in a previous article on the data of Cycles 12-23. The hemispheric phase lags exhibited a characteristic variation: the leading role has been exchanged between the hemispheres by four cycles. The present work extends the investigation of this variation with the data of Schwabe and Staudacher in Cycles 1-4 and 7-10 as well as Sp\"orer's data in cycle 11. The previously found variation can not be clearly recognized using the data of Staudacher, Schwabe and Sp\"orer. However, it is more interesting that the phase lags of the reversals of the magnetic fields at the poles follow the same variation as that of the hemispheric cycles in Cycles 12-23, i.e. in four cyles one of the hemispheres leads and the leading role jumps to the opposite hemisphere in the next four cycles. This means that this variation is a long term property of the entire solar dynamo mechanism, both the toroidal and poloidal fields, that hints at an unidentified component of the process responsible for the long term memory.