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Title: DISTRIBUTION OF MAGNETIC BIPOLES ON THE SUN OVER THREE SOLAR CYCLES

Abstract

We employ synoptic full disk longitudinal magnetograms to study latitudinal distribution and orientation (tilt) of magnetic bipoles in the course of sunspot activity during cycles 21, 22, and 23. The data set includes daily observations from the National Solar Observatory at Kitt Peak (1975-2002) and Michelson Doppler Imager on board the Solar and Heliospheric Observatory (MDI/SOHO, 1996-2009). Bipole pairs were selected on the basis of proximity and flux balance of two neighboring flux elements of opposite polarity. Using the area of the bipoles, we have separated them into small quiet-Sun bipoles (QSBs), ephemeral regions (ERs), and active regions (ARs). We find that in their orientation, ERs and ARs follow Hale-Nicholson polarity rule. As expected, AR tilts follow Joy's law. ERs, however, show significantly larger tilts of opposite sign for a given hemisphere. QSBs are randomly oriented. Unlike ARs, ERs also show a preference in their orientation depending on the polarity of the large-scale magnetic field. These orientation properties may indicate that some ERs may form at or near the photosphere via the random encounter of opposite polarity elements, while others may originate in the convection zone at about the same location as ARs. The combined latitudinal distribution of ERs andmore » ARs exhibits a clear presence of Spoerer's butterfly diagram (equatorward drift in the course of a solar cycle). ERs extend the ARs' 'wing' of the butterfly diagram to higher latitudes. This high latitude extension of ERs suggests an extended solar cycle with the first magnetic elements of the next cycle developing shortly after the maximum of the previous cycle. The polarity orientation and tilt of ERs may suggest the presence of poloidal fields of two configurations (new cycle and old cycle) in the convection zone at the declining phase of the sunspot cycle.« less

Authors:
;  [1]
  1. Kislovodsk Solar Station of Pulkovo Observatory (Russian Federation)
Publication Date:
OSTI Identifier:
21452870
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 717; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/717/1/357; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; MAGNETIC FIELDS; MAGNETISM; PHOTOSPHERE; SOLAR CYCLE; SUN; SUNSPOTS; ATMOSPHERES; MAIN SEQUENCE STARS; SOLAR ACTIVITY; SOLAR ATMOSPHERE; STARS; STARSPOTS; STELLAR ACTIVITY; STELLAR ATMOSPHERES

Citation Formats

Tlatov, Andrey G, Vasil'eva, Valerya V, and Pevtsov, Alexei A., E-mail: tlatov@mail.r, E-mail: apevtsov@nso.ed. DISTRIBUTION OF MAGNETIC BIPOLES ON THE SUN OVER THREE SOLAR CYCLES. United States: N. p., 2010. Web. doi:10.1088/0004-637X/717/1/357.
Tlatov, Andrey G, Vasil'eva, Valerya V, & Pevtsov, Alexei A., E-mail: tlatov@mail.r, E-mail: apevtsov@nso.ed. DISTRIBUTION OF MAGNETIC BIPOLES ON THE SUN OVER THREE SOLAR CYCLES. United States. https://doi.org/10.1088/0004-637X/717/1/357
Tlatov, Andrey G, Vasil'eva, Valerya V, and Pevtsov, Alexei A., E-mail: tlatov@mail.r, E-mail: apevtsov@nso.ed. 2010. "DISTRIBUTION OF MAGNETIC BIPOLES ON THE SUN OVER THREE SOLAR CYCLES". United States. https://doi.org/10.1088/0004-637X/717/1/357.
@article{osti_21452870,
title = {DISTRIBUTION OF MAGNETIC BIPOLES ON THE SUN OVER THREE SOLAR CYCLES},
author = {Tlatov, Andrey G and Vasil'eva, Valerya V and Pevtsov, Alexei A., E-mail: tlatov@mail.r, E-mail: apevtsov@nso.ed},
abstractNote = {We employ synoptic full disk longitudinal magnetograms to study latitudinal distribution and orientation (tilt) of magnetic bipoles in the course of sunspot activity during cycles 21, 22, and 23. The data set includes daily observations from the National Solar Observatory at Kitt Peak (1975-2002) and Michelson Doppler Imager on board the Solar and Heliospheric Observatory (MDI/SOHO, 1996-2009). Bipole pairs were selected on the basis of proximity and flux balance of two neighboring flux elements of opposite polarity. Using the area of the bipoles, we have separated them into small quiet-Sun bipoles (QSBs), ephemeral regions (ERs), and active regions (ARs). We find that in their orientation, ERs and ARs follow Hale-Nicholson polarity rule. As expected, AR tilts follow Joy's law. ERs, however, show significantly larger tilts of opposite sign for a given hemisphere. QSBs are randomly oriented. Unlike ARs, ERs also show a preference in their orientation depending on the polarity of the large-scale magnetic field. These orientation properties may indicate that some ERs may form at or near the photosphere via the random encounter of opposite polarity elements, while others may originate in the convection zone at about the same location as ARs. The combined latitudinal distribution of ERs and ARs exhibits a clear presence of Spoerer's butterfly diagram (equatorward drift in the course of a solar cycle). ERs extend the ARs' 'wing' of the butterfly diagram to higher latitudes. This high latitude extension of ERs suggests an extended solar cycle with the first magnetic elements of the next cycle developing shortly after the maximum of the previous cycle. The polarity orientation and tilt of ERs may suggest the presence of poloidal fields of two configurations (new cycle and old cycle) in the convection zone at the declining phase of the sunspot cycle.},
doi = {10.1088/0004-637X/717/1/357},
url = {https://www.osti.gov/biblio/21452870}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 717,
place = {United States},
year = {Thu Jul 01 00:00:00 EDT 2010},
month = {Thu Jul 01 00:00:00 EDT 2010}
}