Rotational Components of the Sun’s Mean Field
This paper uses wavelet transforms to look for the rotational frequencies of the Sun’s mean line-of-sight magnetic field. For a sufficiently high wavelet frequency, the spectra of the dipole, quadrupole, and hexapole field components each show a time-dependent fine structure with periods in the rang...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/acfc4a |
| _version_ | 1797448991095390208 |
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| author | Neil R. Sheeley Jr. |
| author_facet | Neil R. Sheeley Jr. |
| author_sort | Neil R. Sheeley Jr. |
| collection | DOAJ |
| description | This paper uses wavelet transforms to look for the rotational frequencies of the Sun’s mean line-of-sight magnetic field. For a sufficiently high wavelet frequency, the spectra of the dipole, quadrupole, and hexapole field components each show a time-dependent fine structure with periods in the range of 26.5–30 days and their harmonics. These maps confirm that a large enhancement of power at 30 days occurred in the dipole field during 1989–1990, as recorded previously using Fourier techniques. In addition, during some years the maps show power at 26.5 days (or its harmonics), which is clearly distinguishable from the rotation period of 26.9–27.0 days at the Sun’s equator. In at least one case, the 26.5-day period was a wave phenomenon caused by the systematic eruption of active regions at progressively more western locations in the Carrington coordinate system, as if the flux were emerging from a fixed longitude in a faster-rotating subsurface layer. Based on previous studies of the mean field, I conclude that the enhanced wavelet patterns in this paper are regions where magnetic flux is emerging in configurations that strengthen the Sun’s horizontal dipole, quadrupole, and hexapole fields, and (in the case of the more slowly rotating patterns) where this flux is being transported to midlatitudes whose rotation periods are in the range of 28–30 days. |
| first_indexed | 2024-03-09T14:18:24Z |
| format | Article |
| id | doaj.art-24d703b8961d4c1b8985fcd6de1227e4 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-09T14:18:24Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-24d703b8961d4c1b8985fcd6de1227e42023-11-28T18:24:27ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-019591710.3847/1538-4357/acfc4aRotational Components of the Sun’s Mean FieldNeil R. Sheeley Jr.0https://orcid.org/0000-0002-6612-3498Visiting Research Scientist, Lunar and Planetary Laboratory, University of Arizona , Tucson, AZ 85721, USAThis paper uses wavelet transforms to look for the rotational frequencies of the Sun’s mean line-of-sight magnetic field. For a sufficiently high wavelet frequency, the spectra of the dipole, quadrupole, and hexapole field components each show a time-dependent fine structure with periods in the range of 26.5–30 days and their harmonics. These maps confirm that a large enhancement of power at 30 days occurred in the dipole field during 1989–1990, as recorded previously using Fourier techniques. In addition, during some years the maps show power at 26.5 days (or its harmonics), which is clearly distinguishable from the rotation period of 26.9–27.0 days at the Sun’s equator. In at least one case, the 26.5-day period was a wave phenomenon caused by the systematic eruption of active regions at progressively more western locations in the Carrington coordinate system, as if the flux were emerging from a fixed longitude in a faster-rotating subsurface layer. Based on previous studies of the mean field, I conclude that the enhanced wavelet patterns in this paper are regions where magnetic flux is emerging in configurations that strengthen the Sun’s horizontal dipole, quadrupole, and hexapole fields, and (in the case of the more slowly rotating patterns) where this flux is being transported to midlatitudes whose rotation periods are in the range of 28–30 days.https://doi.org/10.3847/1538-4357/acfc4aSolar magnetic fieldsSolar rotationSolar cycleStellar magnetic fields |
| spellingShingle | Neil R. Sheeley Jr. Rotational Components of the Sun’s Mean Field The Astrophysical Journal Solar magnetic fields Solar rotation Solar cycle Stellar magnetic fields |
| title | Rotational Components of the Sun’s Mean Field |
| title_full | Rotational Components of the Sun’s Mean Field |
| title_fullStr | Rotational Components of the Sun’s Mean Field |
| title_full_unstemmed | Rotational Components of the Sun’s Mean Field |
| title_short | Rotational Components of the Sun’s Mean Field |
| title_sort | rotational components of the sun s mean field |
| topic | Solar magnetic fields Solar rotation Solar cycle Stellar magnetic fields |
| url | https://doi.org/10.3847/1538-4357/acfc4a |
| work_keys_str_mv | AT neilrsheeleyjr rotationalcomponentsofthesunsmeanfield |