The cosmic-ray 1.68-year variation: A clue to understand the nature of the solar cycle?

Autor: J. F. Valdés-Galicia, R. Perez-Enriquez, J. A. Otaola
Rok vydání: 1996
Předmět:
Zdroj: Solar Physics. 167:409-417
ISSN: 1573-093X
0038-0938
Popis: Using the maximum entropy method (MEM), the cosmic-ray power spectral density in the frequency range 3 × 10−9–2 × 10−7 Hz has been estimated for the period 1947–1990. Cosmic-ray intensity data were integrated from the ion chamber at Huancayo and the neutron monitor at Deep River, following the method of Nagashima and Morishita (1980). The estimated spectrum shows power-law dependence (f−1.62), with several peaks superimposed. Periodicities of the different peaks are identified and related to solar activity phenomena; most of them were reported in the past. Once the 11-yr variation is eliminated, the most prominent feature in the spectrum is a variation, not reported before, with a period of 1.68 yr (604.8 d). This peak is correlated with fluctuations of similar periodicities found in the southern coronal hole area and in large active regions. The importance that this variation may have to elucidate the solar magnetic flux emergence and the activity cycle is discussed.
Databáze: OpenAIRE
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