Abstract Solar-terrestrial environment is manifested primarily by the physical conditions of the solar interior, solar atmosphere and eruptive solar plasma. Each parameter gives unique information about the Sun and its activity according to its defined characteristics. Hence the variability of solar parameters is of interest from the point of view of plasma dynamics on the Sun and into the interplanetary space as well as for the solar-terrestrial physics. In this study, we have analysed various solar and related parameters to examine the status of solar activity during solar cycles 21, 22, 23 and 24. The correlation coefficients of the linear regression of F10.7 cm index, Lyman alpha index, Mg II index, cosmic ray intensity, number of M & X class flares and coronal mass ejections (CMEs) occurrence rate versus sunspot number were analysed. A running cross-correlation method has been used to study the momentary relationship among the above mentioned solar activity parameters. Solar cycle 21 witnessed the highest value of correlation for F10.7 cm index, Lyman alpha index and number of M-class & X - class flares versus sunspot number among all the considered solar cycles which were about 0.979, 0.935 and 0.964 respectively. Solar cycle 22 recorded the highest correlation in case of Mg II index, Ap index and CMEs occurrence rate versus sunspot number among all the considered solar cycles (0.964, 0.384 and 0.972 respectively). Solar cycle 23 and 24 did not witness any highest correlation compared to solar cycle 21 and 22. Further the record values (highest value compared to other solar cycles) of each solar activity parameters for each of the four solar cycles have been studied. Solar cycle 24 has no record text at all, this simply indicating that this cycle was a weakest cycle compared to the three previous ones. Thus in every domain solar 24 has been observed weaker in comparison of its three predecessors.
Elucidation of some solar parameters observed during solar cycles 21–24
Advances in Space Research ; 68 , 6 ; 2643-2660
2021-04-22
18 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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