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

✍ Scribed by J. F. Valdés-Galicia; R. Pérez-Enríquez; J. A. Otaola

• Publisher: Springer
• Year: 1996
• Tongue: English
• Weight: 454 KB
• Volume: 167
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00146349

✦ Synopsis

Using the maximum entropy method (MEM), the cosmic-ray power spectral density in the frequency range 3 x 10-9-2 • 10-Hz has been estimated for the period . 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 ll-yr variation is eliminated, the most prominent feature in the spectrum is a variation, not reported before, with a period of L68 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.