Cosmic meteorology

Lockwood, Mike; Owens, Mat

doi:10.1093/astrogeo/atab065

Cited by 4 publications

(3 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When the height of the source surface in the PFSS model is lowered, these closed magnetic field lines persist very low down, close to the surf ace. Tow ards the end of the Maunder minimum (which is a grand minimum phase), a few solar eclipse paintings and simulations show a structure-less large-scale solar atmosphere (Riley et al 2015 ;Hayakawa et al 2021 ;Lockwood & Owens 2021 ). We surmise that less solar open field lines (and lower open flux) during grand minima phases -resulting from the surface field distribution go v erned by the solar dynamo output -culminates in a weaker driving of the solar wind.…”

Section: O N C L U D I N G Discussion Smentioning

confidence: 69%

“…In order to understand the coronal structure during a grand minimum phase, Riley et al ( 2015 ) modelled coronal magnetic fields using global magnetohydrodynamic simulations. Global solar coronal configuration for past eclipses during grand minimum episodes is also explored by Hayakawa et al ( 2020Hayakawa et al ( , 2021; Lockwood & Owens ( 2021 ) using historic paintings.…”

mentioning

confidence: 99%

See 1 more Smart Citation

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

Dash

Nandy

Usoskin

2023

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

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 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; lack of coronal field observations compound 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.

show abstract

Section: O N C L U D I N G Discussion Smentioning

confidence: 69%

mentioning

confidence: 99%

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

Dash

Nandy

Usoskin

2023

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

show abstract

“…Frontiers in Astronomy and Space Sciences frontiersin.org (Lockwood and Owens, 2014;Owens et al, 2017a;Lockwood and Owens, 2021) and has been used to interpret eclipse observations in and immediately after the Maunder minimum by Hayakawa et al (2021). The relationship at sunspot minimum shown in Figure 2 is expected because at sunspot minimum a big part of F S is the OSF in polar coronal holes, F CH , and larger F CH means larger area of those polar coronal holes and so a smaller streamer belt width Λ SB (Makarov et al, 2003).…”

Section: Figurementioning

confidence: 99%

Application of historic datasets to understanding open solar flux and the 20th-century grand solar maximum. 2. Solar observations

Lockwood

Owens

Yardley

et al. 2022

Front. Astron. Space Sci.

Self Cite

View full text Add to dashboard Cite

We study historic observations of solar activity from the 20th-century rise towards the peak of the Modern Grand Solar Maximum (MGSM) and compare with observations of the decline that has occurred since. The major difference in available solar observations of the rise and of the fall are accurate magnetograms from solar magnetographs: we here use synthetic magnetograms to interpret the rise and employ historic observations of Polar Crown Filaments to test them and verify their use. We show that eclipse images at sunspot minimum reveal the long-term variation of open flux deduced from geomagnetic observations in Paper 1 (Lockwood et al., 2022). We also make use of polar coronal hole fluxes derived from historic white light images of polar faculae, but have to consider the implications of the fact that these facular images do not tell us the polarity of the field. Given this caveat, the agreement between the polar coronal hole fluxes and the values derived from open flux continuity modelling based on sunspot numbers is extremely good. This comparison indicates that one possible solution to the “open flux problem” is open flux within the streamer belt that potential-based modelling of coronal fields from photospheric fields is not capturing. We take a detailed look at the solar cycle at the peak of the MGSM, cycle 19, and show the variation of the polar coronal hole fluxes and the inferred poleward flux surges are predictable from the asymmetries in flux emergence in the two hemispheres with implied transequatorial flux transfer and/or “anti-Hale” (or more general “rogue” active region flux) emergence late in the sunspot cycle.

show abstract

Reconstructing Sunspot Number by Forward-Modelling Open Solar Flux

Owens,

Lockwood,

Barnard

et al. 2024

Sol Phys

View full text Add to dashboard Cite

The open solar flux (OSF) is the integrated unsigned magnetic flux leaving the top of the solar atmosphere to form the heliospheric magnetic field. As the OSF modulates the intensity of galactic cosmic rays at Earth, the production rate of cosmogenic isotopes – such as 14C and 10Be stored in tree rings and ice sheets – is closely related to the OSF. Thus on the basis of cosmogenic isotope data, OSF can be reconstructed over millennia. As sunspots are related to the production of OSF, this provides the possibility of reconstructing sunspot number (SSN) and hence properties of the solar cycles prior to the first sunspot telescopic observations in 1610. However, while models exist for estimating OSF on the basis of SSN, the hysteresis present in OSF and the lack of a priori knowledge of the start/end dates of individual solar cycles means that directly inverting these models is not possible. We here describe a new method that uses a forward model of OSF to estimate SSN and solar cycle start/end dates through a Monte Carlo approach. The method is tested by application to geomagnetic reconstructions of OSF over the period 1845-present, and compared to the known SSN record for this period. There is a substantial improvement in reconstruction of both the SSN time series and the solar cycle start/end dates compared with existing OSF-SSN regression methods. This suggests that more accurate solar-cycle information can be extracted from cosmogenic isotope records by forward modelling, and also provides a means to assess the level of agreement between independent SSN and OSF reconstructions. We find the geomagnetic OSF and observed SSN agree very well after 1875, but do differ during the early part of the geomagnetic record, though still agree within the larger observational uncertainties.

show abstract

Cosmic meteorology

Abstract: Mike Lockwood and Mat Owens discuss how eclipse observations are aiding the development of a climatology of near-Earth space

Cited by 4 publications

References 29 publications

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

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

Application of historic datasets to understanding open solar flux and the 20th-century grand solar maximum. 2. Solar observations

Reconstructing Sunspot Number by Forward-Modelling Open Solar Flux

Contact Info

Product

Resources

About