Algebraic Quantification of the Contribution of Active Regions to the Sun's Dipole Moment: Applications to Century-scale Polar Field Estimates and Solar Cycle Forecasting

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Hauptverfasser: Pal, Shaonwita, Nandy, Dibyendu
Format: Preprint
Veröffentlicht: 2023
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author Pal, Shaonwita
Nandy, Dibyendu
author_facet Pal, Shaonwita
Nandy, Dibyendu
contents The solar cycle is generated by a magnetohydrodynamic dynamo mechanism which involves the induction and recycling of the toroidal and poloidal components of the Sun's magnetic field. Recent observations indicate that the Babcock-Leighton mechanism -- mediated via the emergence and evolution of tilted bipolar active regions -- is the primary contributor to the Sun's large-scale dipolar field. Surface flux transport models and dynamo models have been employed to simulate this mechanism, which also allows for physics-based solar cycle forecasts. Recently, an alternative analytic method has been proposed to quantify the contribution of individual active regions to the Sun's dipole moment. Utilizing solar cycle observations spanning a century, here, we test the efficacy of this algebraic approach. Our results demonstrate that the algebraic quantification approach is reasonably successful in estimating dipole moments at solar minima over the past century -- providing a verification of the Babcock-Leighton mechanism as the primary contributor to the Sun's dipole field variations. We highlight that this algebraic methodology serves as an independent approach for estimating dipole moments at the minima of solar cycles, relying on characteristics of bipolar solar active regions. We also show how this method may be utilized for solar cycle predictions; our estimate of the Sun's dipole field at the end of cycle 24 using this approach indicates that solar cycle 25 would be a moderately weak cycle, ranging between solar cycle 20 and cycle 24.
format Preprint
id arxiv_https___arxiv_org_abs_2312_15703
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Algebraic Quantification of the Contribution of Active Regions to the Sun's Dipole Moment: Applications to Century-scale Polar Field Estimates and Solar Cycle Forecasting
Pal, Shaonwita
Nandy, Dibyendu
Solar and Stellar Astrophysics
The solar cycle is generated by a magnetohydrodynamic dynamo mechanism which involves the induction and recycling of the toroidal and poloidal components of the Sun's magnetic field. Recent observations indicate that the Babcock-Leighton mechanism -- mediated via the emergence and evolution of tilted bipolar active regions -- is the primary contributor to the Sun's large-scale dipolar field. Surface flux transport models and dynamo models have been employed to simulate this mechanism, which also allows for physics-based solar cycle forecasts. Recently, an alternative analytic method has been proposed to quantify the contribution of individual active regions to the Sun's dipole moment. Utilizing solar cycle observations spanning a century, here, we test the efficacy of this algebraic approach. Our results demonstrate that the algebraic quantification approach is reasonably successful in estimating dipole moments at solar minima over the past century -- providing a verification of the Babcock-Leighton mechanism as the primary contributor to the Sun's dipole field variations. We highlight that this algebraic methodology serves as an independent approach for estimating dipole moments at the minima of solar cycles, relying on characteristics of bipolar solar active regions. We also show how this method may be utilized for solar cycle predictions; our estimate of the Sun's dipole field at the end of cycle 24 using this approach indicates that solar cycle 25 would be a moderately weak cycle, ranging between solar cycle 20 and cycle 24.
title Algebraic Quantification of the Contribution of Active Regions to the Sun's Dipole Moment: Applications to Century-scale Polar Field Estimates and Solar Cycle Forecasting
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2312.15703