Solar Open Flux Migration from Pole to Pole: Magnetic Field Reversal

Huang, Guan-Han; Lin, Chia Hsien; Lee, L. C.

doi:10.1038/s41598-017-09862-2

Cited by 10 publications

(6 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The second is equatorward migration of coronal hole flux and OSF from both poles in the subsequent rising phase of the next cycle. The latter has been seen in studies using PFSS modelling (Wang and Sheeley, 1994;Bilenko and Tavastsherna, 2016;Huang et al, 2017) and also in studies of coronal hole distributions seen in infra-red maps and using fulldisk magnetograms to determine the field polarity (Bilenko, 2002). This pole-to-pole migration takes place simultaneously for the two polarities at different longitudes.…”

Section: Changes In the Spatial Distribution Of Osf Over The Sunspot ...mentioning

confidence: 78%

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.

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

Section: Changes In the Spatial Distribution Of Osf Over The Sunspot ...mentioning

confidence: 78%

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.

View full text Add to dashboard Cite

show abstract

“…Our results indicate that these CHs without OP1 are on average smaller and less unipolar than the CHs with open magnetic field lines. Such coronal holes are unlikely to be the source regions of high-speed solar winds, and can be one reason for the low consistency level between CHs and high-speed solar wind source regions reported by Huang et al (2017).…”

Section: Discussionmentioning

confidence: 93%

“…However, more recent studies have shown significant inconsistency between the CHs and the source regions of high-speed solar wind (e.g., Huang et al 2017), and between CHs and OMF regions (e.g., Obridko & Shelting 1999;Lowder et al 2014Lowder et al , 2017Linker et al 2017;Huang et al 2017Huang et al , 2019. Part of the inconsistency can be caused by methodological inaccuracy.…”

Section: Introductionmentioning

confidence: 99%

Existence of The Closed Magnetic Field Lines Crossing The Coronal Hole Boundaries

Huang,

Lin,

Lee

2022

Preprint

View full text Add to dashboard Cite

Coronal holes (CHs) are regions with unbalanced magnetic flux, and have been associated with open magnetic field (OMF) structures. However, it has been reported that some CHs do not intersect with OMF regions. To investigate the inconsistency, we apply a potential-field (PF) model to construct the magnetic fields of the coronal holes. As a comparison, we also use a thermodynamic magnetohydrodynamic (MHD) model to synthesize coronal images, and identify CHs from the synthetic images. The results from both the potential-field CHs and synthetic MHD CHs reveal that there is a significant percentage of closed field lines extending beyond the CH boundaries and more than 50% (17%) of PF (MHD) CHs do not contain OMF lines. The boundary-crossing field lines are more likely to be found in the lower latitudes during active times. While they tend to be located slightly closer than the non-boundary-crossing ones to the CH boundaries, nearly 40% (20%) of them in PF (MHD) CHs are not located in the boundary regions. The CHs without open field lines are often smaller and less unipolar than those with open field lines. The MHD model indicates higher temperature variations along the boundary-crossing field lines than the non-boundary crossing ones. The main difference between the results of the two models is that the dominant field lines in the PF and MHD CHs are closed and open field lines, respectively.

show abstract

“…Our results indicate that these CHs without OP1 are on average smaller and less unipolar than the CHs with open magnetic field lines. Such CHs are unlikely to be the source regions of high-speed solar winds and can be one reason for the low consistency level between CHs and high-speed solar wind source regions reported by Huang et al (2017).…”

Section: Discussionmentioning

confidence: 93%

“…However, more recent studies have shown significant inconsistency between the CHs and the source regions of high-speed solar wind (e.g., Huang et al 2017) and between CHs and OMF regions (e.g., Obridko & Shelting 1999;Lowder et al 2014;Huang et al 2017;Linker et al 2017;Lowder et al 2017;Huang et al 2019). Part of the inconsistency can be caused by methodological inaccuracy.…”

Section: Introductionmentioning

confidence: 99%

Existence of the Closed Magnetic Field Lines Crossing the Coronal Hole Boundaries

Huang

Lin

Lee

2022

ApJ

View full text Add to dashboard Cite

Coronal holes (CHs) are regions with unbalanced magnetic flux and have been associated with open magnetic field (OMF) structures. However, it has been reported that some CHs do not intersect with OMF regions. To investigate the inconsistency, we apply a potential-field (PF) model to construct the magnetic fields of the CHs. As a comparison, we also use a thermodynamic magnetohydrodynamic (MHD) model to synthesize coronal images and identify CHs from the synthetic images. The results from both the potential-field CHs and synthetic MHD CHs reveal that there is a significant percentage of closed field lines extending beyond the CH boundaries and more than 50% (17%) of PF (MHD) CHs do not contain OMF lines. The boundary-crossing field lines are more likely to be found in the lower latitudes during active times. While they tend to be located slightly closer than the non-boundary-crossing ones to the CH boundaries, nearly 40% (20%) of them in PF (MHD) CHs are not located in the boundary regions. The CHs without open field lines are often smaller and less unipolar than those with open field lines. The MHD model indicates higher temperature variations along the boundary-crossing field lines than the non-boundary-crossing ones. The main difference between the results of the two models is that the dominant field lines in the PF and MHD CHs are closed and open field lines, respectively.

show abstract

Solar Open Flux Migration from Pole to Pole: Magnetic Field Reversal

Cited by 10 publications

References 27 publications

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

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

Existence of The Closed Magnetic Field Lines Crossing The Coronal Hole Boundaries

Existence of the Closed Magnetic Field Lines Crossing the Coronal Hole Boundaries

Contact Info

Product

Resources

About