Synoptic study of the attenuation coefficients for the cosmic-ray neutron monitors of the IGY network from 1957 to 1965

1967 ◽  
Vol 52 (1) ◽  
pp. 106-123 ◽  
Author(s):  
F. Bachelet ◽  
E. Dyring ◽  
N. Iucci ◽  
G. Villoresi
Keyword(s):  
Cosmic Ray ◽  
Neutron Monitors ◽  
Attenuation Coefficients

Time changes of the attenuation coefficients for cosmic-ray neutron monitors

1968 ◽  
Vol 46 (10) ◽  
pp. S1041-S1043 ◽  
Author(s):  
F. Bachelet ◽  
E. Dyring ◽  
N. Iucci ◽  
G. Villoresi
Keyword(s):  
Regression Analysis ◽  
Solar Cycle ◽  
Sea Level ◽  
Time Variation ◽  
Cosmic Ray ◽  
Neutron Monitors ◽  
Attenuation Coefficients ◽  
Daily Data ◽  
Independent Estimate ◽  
Time Changes

The time variation of the attenuation coefficients is synoptically studied by regression analysis on reduced and filtered daily data of 21 IGY neutron monitors from 1957 to 1965 and 11 IQSY supermonitors from 1964 to 1966. For the sea-level IGY monitors at high latitude a typical peak-to-peak amplitude of 4% is found for the solar-cycle change, in agreement with an independent estimate of the effect. The supermonitor results show, as expected, no relevant time variation in the period studied and smaller differences than the IGY monitors among stations of similar geophysical conditions.Attenuation coefficients obtained by mobile monitor measurements in 1967 are also presented.

Attenuation coefficients of the cosmic-ray nucleonic component in the lower atmosphere

1965 ◽  
Vol 35 (1) ◽  
pp. 23-35 ◽  
Author(s):  
F. Bachelet ◽  
P. Balata ◽  
E. Dyring ◽  
N. Iucci
Keyword(s):  
Cosmic Ray ◽  
Lower Atmosphere ◽  
Attenuation Coefficients ◽  
Nucleonic Component

Daily variation of cosmic rays during quiet and disturbed periods in 1965 and 1966

1968 ◽  
Vol 46 (10) ◽  
pp. S819-S822
Author(s):  
Pekka J. Tanskanen
Keyword(s):  
Daily Variation ◽  
Cosmic Ray ◽  
Ecliptic Plane ◽  
Neutron Monitors ◽  
Monthly Basis ◽  
Cosmic Ray Intensity ◽  
Variable Amplitude ◽  
Ecliptic Latitude ◽  
Streaming Velocity ◽  
Corrected Data

Data from super neutron monitors at Deep River, Churchill, Resolute, and Alert have been used to study the daily variation of cosmic-ray intensity during 1965 and 1966. Intensities have been examined on a daily, weekly, and monthly basis as a function of the asymptotic direction of vertically incident 7.5-BeV particles. The data have been analyzed in an earth-centered solar-ecliptic coordinate system in which daily (due to the earth's rotation) and seasonal (due to the inclination of the earth's axis to the ecliptic plane) variations of the asymptotic directions are considered.During undisturbed periods the daily variation has been examined by applying a digital filter to the pressure-corrected data and also to the data after subtraction of a variable-amplitude Parker–Axford theoretical diurnal variation. Particular attention has been paid to the dependence of the observed daily variation on the solar-ecliptic latitude of the asymptotic direction.Seventy-three percent of the weeks considered in 1965 and 1966 give the phase of the first harmonic in a direction 85° ± 35 °E. Sixty percent of the weekly periods show a daily variation as a function of solar-ecliptic latitude which is in agreement with the Parker–Axford "streaming-velocity" theory. During Forbush decreases the diurnal phase shifts towards earlier hours and the amplitude increases to two to three times the predecrease level.

THE EFFECTIVE DIRECTIONAL SENSITIVITY OF COSMIC-RAY NEUTRON MONITORS

1961 ◽  
Vol 39 (5) ◽  
pp. 668-676 ◽  
Author(s):  
S. M. Lapointe ◽  
D. C. Rose
Keyword(s):  
Energy Spectrum ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
The Other ◽  
Directional Sensitivity ◽  
Master Curves ◽  
Neutron Monitors ◽  
Atmospheric Absorption ◽  
Method Of Calculation ◽  
Set Of Points

The direction of maximum sensitivity of a neutron monitor is calculated numerically for a set of points on the same geomagnetic meridian but extending in latitude from the equator to the pole. This leads to two master curves, one for the longitude, the other for the latitude of this direction. From these curves this direction is obtained in geographic co-ordinates for some 20 cosmic-ray stations. The method of calculation is described taking into account atmospheric absorption and the energy spectrum of the incident particles. The aperture of the sensitive cone, or source width, is also calculated. Finally the accuracy of the results is discussed and the application of the concept of effective direction is described.

Diurnal cosmic-ray variation with the inclusion of the geometrical effects and the asymptotic cones of approach

1968 ◽  
Vol 46 (10) ◽  
pp. S809-S811 ◽  
Author(s):  
L. I. Dorman ◽  
S. Fischer
Keyword(s):  
Spatial Distribution ◽  
High Latitude ◽  
Intensity Variation ◽  
Cosmic Ray ◽  
The Sun ◽  
Neutron Monitors ◽  
Asymptotic Cones ◽  
Diurnal Anisotropy ◽  
Geometrical Effects

Employing the data from cosmic-ray neutron monitors at high latitude, the spatial distribution of the axis of the diurnal anisotropy is determined. The effects of the earth's revolution around the sun on the diurnal intensity variation is investigated. A new method for further investigation of the spatial distribution of the anisotropy and for the determination of its spectra in various directions has been proposed.

scholarly journals Wavelet analysis of long-term variations in neutron monitor, sunspot number and interplanetary magnetic field data

2021 ◽  
pp. 39-42
Author(s):  
Fraser Baird ◽  
Alexander MacKinnon
Keyword(s):  
Magnetic Field ◽  
Field Data ◽  
Solar Magnetic Field ◽  
Cosmic Ray ◽  
Negative Polarity ◽  
Neutron Monitors ◽  
Magnetic Field Data ◽  
First Time ◽  
Long Term Variations

For the first time, based on the experimental data of AMS-02, a three-parameter spectrum of variations of ga - lactic cosmic rays was obtained in the range of rigidity 1- 20 GV, to which neutron monitors are most sensitive. It was found that during the period of negative polarity of the solar magnetic field, a power-law spectrum of va - riations is observed with a strong exponential decay in the region of high rigidity. When the polarity changes to positive at the beginning of the new 24th solar cycle, the spectrum of cosmic ray variations becomes purely po- wer-law. The transition to the experimentally obtained spectrum of variations will make it possible to remove a number of uncertainties and increase the accuracy of the analysis of data from the ground network of detectors. This will make it possible to retrospectively obtain fluxes of galactic protons with an average monthly resolution for the period of the space era based on ground-based monitoring.

scholarly journals Variations of Interplanetary Parameters and Cosmic-Ray Intensities

1980 ◽  
Vol 91 ◽  
pp. 393-398
Author(s):  
A. Geranios
Keyword(s):  
Solar Flare ◽  
Recovery Time ◽  
Propagation Speed ◽  
Cosmic Ray ◽  
Interplanetary Shocks ◽  
Fast Solar Wind ◽  
Neutron Monitors ◽  
Cosmic Ray Intensity ◽  
Cosmic Ray Modulation ◽  
Modulation Region

Observations of cosmic ray intensity depressions by earth bound neutron monitors and measurements of interplanetary parameter's variations aboard geocentric satellites in the period January 1972-July 1974 are analysed and grouped according to their correlation among them. From this analysis of about 30 cases it came out that the majority of the depressions correlates with the average propagation speed of interplanetary shocks as well as with the amplitude of the interplanetary magnetic field after the eruption of a solar flare. About one fourth of the events correlates with corotating fast solar wind streams. As the recovery time of the shock-related depressions depends strongly on the heliographic longitude of the causitive solar flare, it seems that the cosmic ray modulation region has a corotative-like feature.

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.

SMALL COSMIC-RAY INCREASES MEASURED AT GROUND LEVEL, SEPTEMBER 3, 1960, JULY 18 AND JULY 20, 1961

1962 ◽  
Vol 40 (5) ◽  
pp. 540-549 ◽  
Author(s):  
B. G. Wilson ◽  
D. C. Rose ◽  
Margaret D. Wilson
Keyword(s):  
Cosmic Ray ◽  
Ground Level ◽  
Strong Impact ◽  
Impact Zone ◽  
Limited Data ◽  
Neutron Monitors ◽  
Small Magnitude ◽  
Cosmic Ray Intensity ◽  
Interplanetary Magnetic Fields ◽  
The Impact

Three small increases in cosmic-ray intensity, observed in high counting rate neutron monitors in Canada, are described and the results examined in relation to the impact zone effect with particular reference to recent studies by McCracken. Pronounced impact zone effects were observed during the July 18, 1961, event, the largest of these three increases, while the September 3, 1960, event showed no such effects. Considerations of the state of the interplanetary magnetic fields at these times show that these results are consistent with McCracken's explanations. The sharp rise to maximum of the July 20, 1961, increase would suggest strong impact zone effects, but such conclusions that can be drawn from the limited data and the small magnitude of the increase suggest that it does not conform with the usual pattern.

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