منابع مشابه
Magnetically Preferred Solar Longitudes: Reality?
The observed persistence of specific periodicities detected in time series associated with solar surface magnetic activity over several solar cycles has led to numerous papers supporting the existence of preferred longitudes. Recent analysis of the past 120 years of sunspot number data showed that no observed periodicity remained coherent for durations greater than two 11-year solar cycles. Her...
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 کاملConnection between Active Longitudes and Magnetic Helicity
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 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...
متن کاملPreferred 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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ژورنال
عنوان ژورنال: Nature
سال: 1886
ISSN: 0028-0836,1476-4687
DOI: 10.1038/035100a0