Periodicities in sunspot activity during solar cycle 23
نویسندگان
چکیده
منابع مشابه
Geomagnetism during solar cycle 23: Characteristics
On the basis of more than 48 years of morphological analysis of yearly and monthly values of the sunspot number, the aa index, the solar wind speed and interplanetary magnetic field, we point out the particularities of geomagnetic activity during the period 1996-2009. We especially investigate the last cycle 23 and the long minimum which followed it. During this period, the lowest values of the...
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Mid-range periodicities in solar flare occurrence have been analyzed with new methods for cycles 19–23. During cycle 23, periodicities of 129-d and 33.5-d were in operation. Five episodes of high activity occurred periodically with the 129-d period. The 33.5-d periodicity mainly operated for energetic flares. Results for cycles 19–21 are generally in agreement with previous analyses. For cycle ...
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Designing a statistical solar flare forecasting technique can benefit greatly from knowledge of the flare frequency of occurrence with respect to sunspot groups. This study analyzed sunspot groups and Hα and X-ray flares reported for the period 1997 – 2007. Annual catalogs were constructed, listing the days that numbered sunspot groups were observed (designated sunspot group-days, SSG-Ds) and f...
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In this paper, we investigate the spatial distribution of solar flares in the northern and southern hemisphere of the Sun that occurred during the period 1996 to 2003. This period of investigation includes the ascending phase, the maximum and part of descending phase of solar cycle 23. It is revealed that the flare activity during this cycle is low compared to previous solar cycle, indicating t...
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ژورنال
عنوان ژورنال: Astronomy & Astrophysics
سال: 2006
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20064978