Active region contributions to the solar wind over multiple solar cycles

Abstract

Both coronal holes and active regions are source regions of the solar wind. The distribution of these coronal structures across both space and time is well known, but it is unclear how much each source contributes to the solar wind. In this study we use photospheric magnetic field maps observed over the past four solar cycles to estimate what fraction of magnetic open solar flux is rooted in active regions, a proxy for the fraction of all solar wind originating in active regions. We find that the fractional contribution of active regions to the solar wind varies between 30% to 80% at any one time during solar maximum and is negligible at solar minimum, showing a strong correlation with sunspot number. While active regions are typically confined to latitudes $\pm$30${}^{\circ }$ in the corona, the solar wind they produce can reach latitudes up to $\pm$60${}^{\circ }$. Their fractional contribution to the solar wind also correlates with coronal mass ejection rate, and is highly variable, changing by $\pm$20% on monthly timescales within individual solar maxima. We speculate that these variations could be driven by coronal mass ejections causing reconfigurations of the coronal magnetic field on sub-monthly timescales.

arXiv comment18 pages, 7 figures. Published in Solar Physics

References in corpus (23)

• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The Solar Orbiter mission -- Science overview
• Magnetic connectivity of the ecliptic plane within 0.5 AU : PFSS modeling of the first PSP encounter
• Numerical Simulation of an EUV Coronal Wave Based on the February 13, 2009 CME Event Observed by STEREO
• Coronal Magnetic Field Evolution from 1996 to 2012: Continuous Non-Potential Simulations
• Coronal magnetic reconnection driven by CME expansion -- the 2011 June 7 event
• Diagnosing solar wind origins using in-situ measurements in the inner heliosphere
• Dynamics of Coronal-Hole Boundaries
• Source of a Prominent Poleward Surge During Solar Cycle 24
• Upflows in the upper solar atmosphere
• Reconstructing coronal hole areas with EUHFORIA and adapted WSA model: optimising the model parameters
• Comparison of Ground- and Space-based Longitudinal Magnetograms
• Coronal sources and in situ properties of the solar winds sampled by ACE during 1999-2008
• Parameter optimization for surface flux transport models
• Signatures of Interchange Reconnection: STEREO, ACE and Hinode Observations Combined
• Low-latitude coronal holes, decaying active regions and global coronal magnetic structure
• Mass Loss via Solar Wind and Coronal Mass Ejections During Solar Cycle 23 and 24
• The drivers of active region outflows into the slow solar wind
• Magnetic Flux Rope Identification and Characterization from Observationally-Driven Solar Coronal Models
• Directly comparing coronal and solar wind elemental fractionation
• Sensitivity of solar wind mass flux to coronal temperature
• Rearrangements of Open Magnetic Flux and Formation of Polar Coronal Holes in Cycle 24
• Interchange reconnection between an active region and a corona hole

Cited by in corpus (7)

• Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
• COCONUT, a novel fast-converging MHD model for solar corona simulations: I. Benchmarking and optimization of polytropic solutions
• Stirring the Base of the Solar Wind: On Heat Transfer and Vortex Formation
• Near subsonic solar wind outflow from an active region
• Evolution of solar wind sources and coronal rotation driven by the cyclic variation of the Sun's large-scale magnetic field
• Slow Solar Wind Connection Science during Solar Orbiter's First Close Perihelion Passage
• Accounting for Differential Rotation in Calculations of the Sun's Angular Momentum-loss Rate