α-ω effect and recurrent changes of galactic cosmic rays intensity

Abstract

We recognize a quasi-recurrence with duration of 3 to 4 Carrington rotations period (3-4 CRP) in changes of amplitudes of the 27-day variation of galactic cosmic rays (GCR) intensity, solar activity (SA) and solar wind (SW) parameters, as well. We attribute this phenomenon to the presence of a spatial topological structure (STS) of the solar magnetic field. STS is created by α-ω effect in the inner solar atmosphere, from photosphere to lower corona. STS exists due to the asymmetry of solar dynamo and solar differential rotation. Studying this phenomenon by the aid of spectral analysis methods we found an existence of the quasi-periodicities with the duration shorter than, and longer than the 3-4 CRP. This 3-4 CRP quasi-periodicity mode corresponds to the extreme interval ∆t of differential rotation periods, ∆t = 35 days-25 days (from poles to equator of the Sun, respectively). We assume also that the process like to α-ω appears in time intervals corresponding to the transitional differential rotation periods, as well, e.g. ∆t1 = 26 days-25 days, ∆t2 = 27 days-25 days, and so forth, to ∆t = 35 days-25 days. We assume that extensive range of quasi-periodicities of GCR intensity, SW and SA parameters can be related to the combined influence of turbulent solar dynamo and solar differential rotation. Thus, STS should be very complex pattern containing a broad modes of oscillations responsible for various types of quasiperiodicities. So, we believe that it is possible to find an evidence that any alternation: periodical or nonperiodical in GCR intensity and in parameters of solar activity and solar wind is strongly related with temporal changes of the various scales of STS.

Hale cycle and long-term trend in variation of galactic cosmic rays related to solar rotation

“…Figure 1 illustrates the dominant 11-yr cycle in A 27 and A 14 with maxima around solar maxima and minima around solar minima (Meyer & Simpson 1954). However, in addition to this 11-yr cycle, there is a systematic 22-yr variation in the level of both amplitudes around solar minima, verifying the above-discussed polarity dependence (Richardson et al 1999;Gil & Alania 2001). The amplitudes of the two harmonics of the GCR intensity variation are larger during each positive-polarity minimum than the corresponding amplitudes during the previous or the following negative-polarity minima.…”

“…The Hale cycle consists of two successive 11-yr solar activity cycles (also called Schwabe cycles) of opposite magnetic field polarities (Hale et al 1919). Alania and coauthors Gil & Alania 2001) confirmed that the 27-day amplitude of GCR variation is larger during positivepolarity minima (A > 0, magnetic field lines directed outward from the northern pole) than negative (A < 0, magnetic field lines directed outward from the southern pole), in contradiction to the expectation (e.g., Kota & Jokipii 1991) that the 27-day variation is the same for both polarities. Kota & Jokipii (2001) used a non-stationary threedimensional model of GCR transport that included a southwardshifted heliospheric current sheet and corotating interaction regions (CIRs) to demonstrate the polarity dependence of rotation-related quasi-periodic variations of GCR intensity.…”

Solar-Heliospheric Physics

“…The 27-day variations due to solar rotation were shown to have an amplitude that varies with the 11-year and 22-year cycles [24]. There was a report of a possible periodicity with a period of 3-4 solar rotations, which could be attributed to differential rotation of the Sun [23]. Diffusion of cosmic rays in the heliosphere was discussed in the context of ground-based muon observations by GRAPES-3 [8].…”