Ca ii K Polar Network Index of the Sun: A Proxy for Historical Polar Magnetic Field

The Sun’s polar magnetic field is pivotal in understanding solar dynamo processes and forecasting future solar cycles. However, direct measurements of the polar field have only been available since the 1970s. The chromospheric Ca ii K polar network index (PNI; the fractional area of the chromospheri...

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Bibliographic Details

Published in:	The Astrophysical Journal
Main Authors:	Dibya Kirti Mishra, Bibhuti Kumar Jha, Theodosios Chatzistergos, Ilaria Ermolli, Dipankar Banerjee, Lisa A. Upton, M. Saleem Khan
Format:	Article
Language:	English
Published:	IOP Publishing 2025-01-01
Subjects:	Magnetic fields Solar cycle Solar chromosphere
Online Access:	https://doi.org/10.3847/1538-4357/adb3a8