The cosmic-ray intensity variations with periods of 19-24 days

1968 ◽  
Vol 46 (10) ◽  
pp. S831-S834
Author(s):  
G. A. Bazilevskaya
Keyword(s):  
Solar Activity ◽  
Sunspot Number ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
High Solar Activity ◽  
Radio Emissions ◽  
Cosmic Ray Intensity ◽  
Cyclic Variations

Sporadic cyclic variations of the cosmic-ray intensity with periods of 19 to 24 days have been found from the results of balloon and neutron monitor observations. These variations were observed mainly in the years of high solar activity, 1958–62. They appeared to be caused by the general solar activity which, as our treatment has shown, undergoes similar cyclic variations (according to sunspot number or 10.7-cm radio-emissions). The variations under investigation appear with a lag of about 1.5 months compared with the solar-activity variations.

HIGH-ALTITUDE COSMIC RAY MEASUREMENTS AT FORT CHURCHILL

1960 ◽  
Vol 38 (5) ◽  
pp. 638-641 ◽  
Author(s):  
I. B. McDiarmid ◽  
D. C. Rose
Keyword(s):  
Solar Activity ◽  
High Altitude ◽  
Solar Minimum ◽  
Solar Maximum ◽  
Cosmic Ray ◽  
Geiger Counter ◽  
Low Energy ◽  
High Solar Activity ◽  
Energy Radiation ◽  
Cosmic Ray Intensity

Measurements with rocket-borne Geiger counters have been carried out at altitudes up to 250 km at Fort Churchill, Manitoba. The total primary cosmic ray intensity at a time near a solar maximum has been determined and compared with other measurements taken at times of high solar activity and also with other Geiger counter measurements obtained near a solar minimum. A low-energy radiation was observed whose intensity increased with altitude up to about 25% of the primary intensity at 250 km.

THE VARIATION OF SEA LEVEL COSMIC RAY INTENSITY BETWEEN 1954 AND 1957

1958 ◽  
Vol 36 (7) ◽  
pp. 824-839 ◽  
Author(s):  
A. G. Fenton ◽  
D. C. Rose ◽  
K. B. Fenton
Keyword(s):  
Solar Activity ◽  
Sea Level ◽  
Geomagnetic Latitude ◽  
Cosmic Ray ◽  
High Solar Activity ◽  
General Level ◽  
Intensity Level ◽  
Cosmic Ray Intensity ◽  
Primary Cosmic Radiation ◽  
The One

Results from neutron monitors and meson telescopes at Ottawa (geomagnetic latitude 57° N.) and Resolute (geomagnetic latitude 83° N.) are presented for the years 1954–57, a period of increasing solar activity. The results indicate that the sea level meson intensity at these latitudes decreased by 5–6% between April 1954 and December 1957. During the same period the intensity of the nucleonic component at these stations decreased by over 22%. Investigation of the relative response of the two types of recorder to transient decreases during this period indicates that the long term change in the intensity level cannot be explained completely as an accumulation of shorter transient decreases, which become more frequent at times of high solar activity. It is concluded that the transient decreases are superimposed upon the longer term changes, each being produced by a separate modulation process but ultimately controlled by the general level of solar activity. Significant differences are found in the shape of transient decreases observed at the Canadian stations, both between different components at the one station and the same component at different stations. These may be interpreted as due to a varying energy dependence from one transient decrease to another, and to anisotropy in the primary cosmic radiation at these times.

ESTABLISHING SOLAR ACTIVITY TREND FOR SOLAR CYCLES 21 – 24

2021 ◽  
Vol 44 ◽  
pp. 100-106
Author(s):  
A.K. Singh ◽  
◽  
A. Bhargawa ◽  
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Sunspot Number ◽  
Cosmic Ray ◽  
Occurrence Rate ◽  
The Sun ◽  
Solar Cycles ◽  
Lyman Alpha ◽  
Rate Versus ◽  
Alpha Index

Solar-terrestrial environment is manifested primarily by the physical conditions of 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 in the interplanetary space as well as for the solar-terrestrial physics. In this study, we have analysed various solar transients and parameters to establish the recent trends of solar activity during solar cycles 21, 22, 23 and 24. The correlation coefficients of 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 was examined for last four solar cycles. 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 and X-class flares versus sunspot number among all the considered solar cycles which were 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 three cycles) of each solar activity parameters for each of the four solar cycles have been studied. Here 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. We have concluded that in every domain solar 24 was weaker to its three predecessors.

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