Journal of Physical Studies 24(1), Article 1901 [7 pages] (2020)
DOI: https://doi.org/10.30970/jps.24.1901

INFLUENCE OF THE ASYMMETRY OF THE SOLAR MAGNETIC FIELD POLARITY REVERSAL ON GEOMAGNETIC ACTIVITY

O. A. Baran1 , M. M. Koval'chuk1 , I. P. Laushnyk2 , M. I. Stodilka1 , M. B. Hirnyak1

1Astronomical Observatory of the Ivan Franko National University of Lviv,
8, Kyryla i Mefodia St., Lviv, UA-79005, Ukraine
e-mail: lesiaab@gmail.com,
2Lviv branch of Dnipro National University of Railway Transport,
12-A, I. Blazhkevych St., 12-A, Lviv, UA-79000, Ukraine

Received 15 July 2019; in final form 10 October 2019; accepted 29 October 2019; published online 05 March 2020

The paper presents the results of a comparative analysis of time series of Wolf numbers, total squares of spots groups, daily characteristics of the solar large-scale magnetic field (LSMF), its two components -- photospheric and polar magnetic fields - with time series of the geomagnetic planetary index $A_{p}$. The cyclic changes of solar and magnetic activity and the asymmetry of magnetic field polarity reversal in two solar hemispheres were observed. The focus of this study was to determine the level of dependence of the geomagnetic activity on the dynamics of magnetic activity during the periods of the solar magnetic field polarity reversal. We used the complete homogeneous data series of magnetographic LSMF measurements (http://wso.stanford.edu), the synoptic maps of photosphere magnetic fields polarities (http://solis.nso.edu), the averaged daily squares of spots groups (http://solarscience.msfc.nasa.gov/greenwch.shtml), and the average daily values of $A_{p}$ (ftp.swpc.noaa.gov/pub/warehouse). The pair of 22-23 cycles and the running 24 cycle of solar activity were investigated. We used a cumulative method of graphical representation of the studied observational data. The results are:

• The north-south asymmetry of spots formation was found during 22-24 cycles. It has been established that the maxima of activity in different hemispheres are shifted by more than 1.5 years. This may be indicative of the independence of the solar cycles’ development in these hemispheres.

• In the leading spots, the polarities change signs at the beginning of each cycle. At the solar poles, the magnetic field polarity reversal takes place during periods of solar activity maximum and not always at the same time. It is supposed that such an evolution of the solar magnetic field leads to the appearance of coronal holes and geomagnetic activity.

• The evolution of the distribution of both solar and geomagnetic activity in the last three cycles (1986-2019) was investigated in detail. The geomagnetic disturbances are not maximal during the period of maximal spots formation, but 1-2 years later. The geomagnetic activity reflects the north-south asymmetry of the solar cycle and also the process of the solar magnetic field polarity reversal assotiated with it.

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