Active longitudes in sunspot activity: Century scale persistence
نویسندگان
چکیده
منابع مشابه
Preferred sunspot longitudes: Non-axisymmetry and differential rotation
As recently found, the distribution of sunspots is non-axisymmetric and spot group formation implies the existence of two persistent active longitudes separated by 180◦. Here we quantitatively study the non-axisymmetry of sunspot occurrence. In a dynamic reference frame inferred from the differential rotation law, the raw sunspot data show a clear clustering around the persistent active longitu...
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We present an overview of the observational results related to the existence of long-lived sunspot active longitudes. These are affected by the solar differential rotation. The existence of such migrating active longitudes imposes an important constraint on the dynamo theory. We review different approaches to model non-axisymmetry in solar dynamo models and find that, in principle, plausible me...
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A two-dimensional mean field dynamo model is solved where magnetic helicity conservation is fully included. The model has a negative radial velocity gradient giving rise to equatorward migration of magnetic activity patterns. In addition the model develops longitudinal variability with activity patches travelling in longitude. These patches may be associated with active longitudes.
متن کاملActive longitudes, nonaxisymmetric dynamos and phase mixing
We discuss the problem of solar active longitudes from the viewpoint of dynamo theory. We start from a recent observational analysis of the problem undertaken by Berdyugina & Usoskin (2003, A&A, 405, 1121) and Usoskin et al. (2005, A&A, 441, 347) who demonstrated from a study of sunspot data that solar active longitudes rotate differentially, with a small but significant asynchrony between nort...
متن کاملComoving frames and active longitudes: Does the Sun have face?
Context. Using Greenwich sunspot data for 120 years it was recently observed that activity regions on the Sun’s surface tend to lie along smoothly changing longitude strips 180◦apart from each other. After critique of the original paper, the new arguments were found to substantiate the claim. Aims. In this paper we analyse new arguments in some detail. Methods. To check basic arguments about pe...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2003
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20030748