Rigidity spectra of primary cosmic radiation

1968 ◽  
Vol 46 (10) ◽  
pp. S923-S926
Author(s):  
K. Kasturirangan ◽  
N. W. Nerurkar
Keyword(s):  
Solar Activity ◽  
North America ◽  
Cosmic Radiation ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Slow Change ◽  
Primary Cosmic Radiation ◽  
Ion Chambers

The comparison of the cosmic-ray intensity measured with balloon-borne ion chambers at different atmospheric depths at stations in North America and in the U.S.S.R. for the period 1937–67 is presented. It is found that there is no difference in variations of cosmic-ray spectra in periods of increasing and decreasing solar activity in 1954–64. In 1937–40 the cosmic-ray spectra are found to be distinctly different, suggesting a slow change in the spectrum over periods greater than the 11-year cycle of solar activity.

scholarly journals 39. The anisotropy of primary cosmic radiation and the electromagnetic state in interplanetary space

1958 ◽  
Vol 6 ◽  
pp. 377-385
Author(s):  
V. Sarabhai ◽  
N. W. Nerurkar ◽  
S. P. Duggal ◽  
T. S. G. Sastry
Keyword(s):  
Experimental Data ◽  
Cosmic Rays ◽  
Cosmic Radiation ◽  
Interplanetary Space ◽  
Daily Variation ◽  
Cosmic Ray ◽  
The Sun ◽  
Cosmic Ray Intensity ◽  
Daily Variations ◽  
Primary Cosmic Radiation

Study of the anisotropy of cosmic rays from the measurement of the daily variation of meson intensity has demonstrated that there are significant day-today changes in the anisotropy of the radiation. New experimental data pertaining to these changes and their solar and terrestrial relationships are discussed.An interpretation of these changes of anisotropy in terms of the modulation of cosmic rays by streams of matter emitted by the sun is given. In particular, an explanation for the existence of the recently discovered types of daily variations exhibiting day and night maxima respectively, can be found by an extension of some ideas of Alfvén, Nagashima, and Davies. An integrated attempt is made to interpret the known features of the variation of cosmic ray intensity in conformity with ideas developed above.

The long-term variation of the cosmic radiation

1968 ◽  
Vol 46 (10) ◽  
pp. S903-S906 ◽  
Author(s):  
J. A. Lockwood ◽  
W. R. Webber
Keyword(s):  
Neutron Monitor ◽  
Cosmic Radiation ◽  
Cosmic Ray ◽  
Solar Modulation ◽  
Neutron Monitors ◽  
Cosmic Ray Intensity ◽  
Direct Measurements ◽  
Term Variation ◽  
Primary Cosmic Radiation

The variation in the cosmic-ray intensity recorded by neutron monitors from 1958 to 1965 has been investigated to deduce the form of the solar modulation of the cosmic radiation. The observed changes in the intensity at the neutron monitor stations, averaged over quarter-year periods, were compared with changes calculated using modulation functions depending upon energy, rigidity, and velocity × rigidity. These calculations were based upon the revised differential response functions deduced by Lockwood and Webber (1967). The variance between the observed and calculated changes in the neutron monitor intensities at different stations was minimized to determine the best form of the solar modulation function. We find that the change of the primary cosmic radiation, deduced from the change in the neutron monitor intensity as well as from direct measurements of the primary flux, can be described by a modulation of the form exp(–K/P) in the rigidity range 0.5 < P < 50 GV. The change between 1959 and 1965 can be fitted with K = 1.94 ± 0.09 and between 1963 and 1965 with K = 0.36 ± 0.05.

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.

A two-way sidereal anisotropy

1968 ◽  
Vol 46 (10) ◽  
pp. S611-S613 ◽  
Author(s):  
K. Nagashima ◽  
H. Ueno ◽  
S. Mori ◽  
S. Sagisaka
Keyword(s):  
Time Variation ◽  
Cosmic Ray ◽  
Sidereal Time ◽  
Cosmic Ray Intensity ◽  
Data Support ◽  
Ion Chambers ◽  
Using Data ◽  
Sidereal Anisotropy

The sidereal time variation is analyzed using data for the ion chambers at Cheltenham and Christchurch for the period 1938–58 and for the meson and neutron components during the IGY. All the results derived from these three kinds of data support the existence of a two-way sidereal anisotropy, suggested by Jacklyn, which has two maxima of the cosmic-ray intensity in the directions of 8 h and 20 h S.T. (sidereal time).

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