Soumyaranjan Dash, Dibyendu Nandy, Ilya Usoskin, Long-term forcing of the Sun’s coronal field, open flux, and cosmic ray modulation potential during grand minima, maxima, and regular activity phases by the solar dynamo mechanism, Monthly Notices of the Royal Astronomical Society, Volume 525, Issue 4, November 2023, Pages 4801–4814, https://doi.org/10.1093/mnras/stad1807
Long-term forcing of the Sun’s coronal field, open flux, and cosmic ray modulation potential during grand minima, maxima, and regular activity phases by the solar dynamo mechanism
|Author:||Dash, Soumyaranjan1; Nandy, Dibyendu1,2; Usoskin, Ilya3|
1Center of Excellence in Space Sciences India, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
2Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, West Bengal, India
3Space Physics and Astronomy Research Unit and Sodankyla Geophysical Observatory, University of Oulu, 90014, Finland
|Online Access:||PDF Full Text (PDF, 2.8 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe20231006139067
Oxford University Press,
|Publish Date:|| 2023-10-06
Magnetic fields generated in the Sun’s interior by the dynamo mechanism drive solar activity over a range of time-scales. Direct sunspot observations exist for a few centuries; reconstructed variations based on cosmogenic isotopes in the solar open flux and cosmic ray flux exist over thousands of years. While such reconstructions indicate the presence of extreme solar activity fluctuations in the past, causal links between millennia scale dynamo activity, consequent coronal field, solar wind, open flux and cosmic ray flux variations remain elusive; a lack of coronal field observations compounds this issue. By utilizing a stochastically forced solar dynamo model and potential field source surface extrapolation, we perform long-term simulations to illuminate how dynamo generated magnetic fields govern the structure of the solar corona and the state of the heliosphere — as indicated by variations in the open flux and cosmic ray modulation potential. We establish differences in the nature of the large-scale structuring of the solar corona during grand maximum, minimum, and regular solar activity phases and simulate how the open flux and cosmic ray modulation potential vary across these different phases of activity. We demonstrate that the power spectrum of simulated and observationally reconstructed solar open flux time series are consistent with each other. Our study provides the theoretical foundation for interpreting long-term solar cycle variations inferred from cosmogenic isotope based reconstructions and establishes causality between solar internal variations to the forcing of the state of the heliosphere.
Monthly notices of the Royal Astronomical Society
|Pages:||4801 - 4814|
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
115 Astronomy and space science
DN acknowledges fruitful exchanges at the Workshop on “Solar and Stellar Dynamos: A New Era” sponsored by the International Space Science Institute, Bern, where the idea of this work was initiated. The authors are thankful to Chitradeep Saha and Shaonwita Pal for helpful discussions. We acknowledge an anonymous referee for useful comments. SD acknowledges PhD fellowship from the DST-INSPIRE program of the Government of India. IU acknowledges partial support by the Academy of Finland (Project ESPERA No. 321882) and a visiting fellowship at ISSI (Bern). The Center of Excellence in Space Sciences India (CESSI) is funded by IISER Kolkata, Ministry of Education, Government of India.
|Academy of Finland Grant Number:||
321882 (Academy of Finland Funding decision)
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2023 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.