Study of periodicities of solar nuclear gamma ray flares and sunspots

Abstract

Here we have carried out a power-spectrum analysis of solar nuclear gamma-ray (NGR) flares observed by SMM and HINOTORI satellites. The solar NGR flares show a periodicity of 152 days, confirming the existence of a 152-158 days periodicity in the occurrence of solar activity phenomena and also indicating that the NGR flares are a separate class of solar flares . The power-spectrum analysis of the daily sunspot areas on the Sun for the period 1980-1982 shows a peak around 159 days while sunspot number data do not show any periodicity (Verma and Joshi, 1987). Therefore, only sunspot area data should be treated as an indicator of solar activity and not the daily sunspot number data. l.IntroductionDuring the solar cycle 21, 152-158 day periodicity was detected in the rate of occurrence of energetic solar flares. This periodicity was first pointed out by Rieger et al. (1984) from the occurrence rate of solar gamma-ray (GR) bursts detected above 300 keY . Rieger et al. (1984) found that soft X-ray bursts also show a 152 day periodicity in the rate of GOES events with classification > M 2.5. Kiplinger et al. (1984) studied larger sample of 6775 solar hard X-ray (HXR) bursts above 30 key and found a 158 day periodicity. Ichimoto et al. (1985) found similar periodicity from H-alpha flare data observed during solar cycles 20 and 21.Bogart and Bai (1985) carried out a power-spectrum study of microwave (MW) emission bursts observed on 1 GHz for the period 1966-1983 and found a 152 day periodicity. Verma and Joshi (1987) analysed strong HXRbursts and sunspot number data for the period 1980-1984 and found a 155 day periodicity in case of strong HXR events and no periodicity in case of sunspot number data. Wolff (1983) carried out Fourier analysis of the variation of the mean monthly sunspot numbers for the period 1799-1979 and found that the most prominent peak below 200 days is 155.4 days, remarkbly close to the period for flares in cycle 21.In the present work, we have carried out a power-spectrumanalysis of daily solar NGR flares, sunspot area data and umbral area data. Observational Data, Analysis and ResultsIn the present investigation we have used data of flares observed by SMM satellite during the period 1980-1985 and HINOTORI satellite during 1981 -1982 The SMM satellite recorded 92 NGR flares (Cliver et ai.,1989).

Periodicities in solar coronal mass ejections

“…Mid‐term quasi‐periodicities (one to several months or longer) in various diagnostics of solar flare activities and sunspot numbers or areas, etc., during a few years around the solar maximum phase have been extensively sought and monitored at many electromagnetic wavelengths (Rieger et al 1984; Kiplinger, Dennis & Orwig 1984; Dennis 1985; Ichimoto et al 1985; Delache, Laclare & Sadsoud 1985; Bogart & Bai 1985; Bai & Sturrock 1987; Ribes et al 1987; Oliver et al 1998; Lean & Brueckner 1989; Özgüç & Ataç 1989; Lean 1990; Carbonell & Ballester 1990; Dröge et al 1990; Pap, Tobiska & Bouwer 1990; Kile & Cliver 1991; Verma, Joshi & Paliwal 1992; Cane, Richardson & von Rosenvinge 1998; Ballester, Oliver & Baudin 1999). These activities of observational research were triggered by the landmark discovery by Rieger et al (1984) of a ∼154 d quasi‐period in solar γ‐ray flare rates registered by the Gamma‐Ray Spectrometer (GRS) on board the Solar Maximum Mission ( SMM ) two decades ago.…”

The Near 160 Day Periodicity in the Photospheric Magnetic Flux

“…For instance, Lean & Brueckner (1989) found that a peak near 155 days was signiÐcant in the periodograms of the sunspot blocking function during solar cycles 19, 20, and 21, both combined and individually, while it was not signiÐcant for the plage index ; Lean (1990) analyzed sunspot area data during solar cycles 12È21, Ðnding that the periodicity is only present during epochs of maximum activity and that it occurs in episodes of 1È3 yr; Pap, Tobiska, & Bouwer (1990) and Bouwer (1992) found the periodicity in "" active ÏÏ sunspot groups, deÐned as newly formed and growing complex groups with c and d magnetic conÐgurations, but not in the Ca K plage index between 1979 and 1987. Also, Carbonell & Ballester (1990 ;, Oliver, Ballester, & Baudin (1998), and Ballester, Oliver, & Baudin (1999), analyzing sunspot areas and group sunspot numbers (Hoyt & Schatten 1998), showed that a periodicity between 150 and 160 days seems to have been signiÐcant during solar cycles 16È21, while Verma, Joshi, & Paliwal (1992) found a periodicity at 159 days in the spot and umbral areas during the time interval 1980È1982.…”

Rossby‐Type Wave–Induced Periodicities in Flare Activities and Sunspot Areas or Groups during Solar Maxima

“…Since the initial discovery of the 154 day Rieger periodicity of solar Ñare rates recorded by the Gamma-Ray Spectrometer (GRS) aboard the Solar Maximum Mission (SMM ; Rieger et al 1984), the periodicities in solar Ñare activities and in sunspot areas or groups during several years around solar maxima have been systematically searched and extensively monitored using various diagnostics and at many electromagnetic wave bands (Rieger et al 1984 ;Kiplinger, Dennis, & Orwig 1984 ;Ichimoto et al 1985 ;Bogart & Bai 1985 ;Dennis 1985 ;Bai & Sturrock 1987, 1991, 1993Bai 1987aBai , 1987bBai , 1992Delache, Laclare, & Sadsoud 1985 ;Ribes et al 1987 ;Lean & Brueckner 1989 ;Lean 1990 ;& 1989 ; ; O zgu cÓ AtacÓ Dro ge Bai & Cliver 1990 ;Carbonell & Ballester 1990 ;Pap, Tobiska, & Bouwer 1990 ;Kile & Cliver 1991 ;Verma, Joshi, & Paliwal 1992 ;Oliver, Ballester, & Baudin 1998 ;Ballester, Oliver, & Baudin 1999). Besides this period range of D150È160 days, other notable Rieger-type periods are D128, 102, 78, and 51 days during maxima of di †erent solar cycles (Bai & Sturrock 1991 ;Bai 1992) from various data sets.…”