Characteristics of Cosmic Ray Diurnal Variation from Deep River Neutron and Meson Data and Temperature Effects

1972 ◽  
Vol 50 (12) ◽  
pp. 1323-1331 ◽  
Author(s):  
S. P. Agrawal ◽  
A. G. Ananth ◽  
U. R. Rao
Keyword(s):  
Solar Cycle ◽  
Diurnal Variation ◽  
Temperature Effects ◽  
Cosmic Ray ◽  
Cutoff Rigidity ◽  
Neutron Data ◽  
Neutron Monitors ◽  
Temperature Coefficients ◽  
Extensive Analysis ◽  
Yield Values

From an extensive analysis of Deep River meson data for over 5 years, new temperature coefficients have been derived for correcting the meson data. It is shown that meson data corrected using new coefficients yield values of diurnal and semidiurnal anisotropy consistent with those obtained from neutron monitors. Using the temperature-corrected meson and neutron data, the upper cutoff rigidity beyond which the diurnal variation ceases is shown to vary with solar cycle showing a minimum of about 35 GV during the Quiet Solar Year of 1965, and a maximum of ≈ 125 GV during 1968–1969.

scholarly journals Temperature Effects on Cosmic Ray muons Observed by Multiwire Detector at High Cutoff Rigidity Station

2019 ◽  
Author(s):  
Abdullrahman Maghrabi ◽  
Abdulah Aldosari ◽  
Mohammed Almutairi ◽  
Mohammed Altilasi ◽  
Abdulah Alshehri ◽  
...  
Keyword(s):  
Temperature Effects ◽  
Cosmic Ray ◽  
Cutoff Rigidity

The relation between latitude and solar-cycle variations in the neutron-monitor mass-absorption coefficient

1968 ◽  
Vol 46 (10) ◽  
pp. S1087-S1089 ◽  
Author(s):  
Miriam A. Forman
Keyword(s):  
Solar Cycle ◽  
Absorption Coefficient ◽  
Sea Level ◽  
Neutron Monitor ◽  
Mass Absorption Coefficient ◽  
Cutoff Rigidity ◽  
Neutron Monitors ◽  
Solar Cycle Variation ◽  
Mass Absorption ◽  
Pressure Altitude

The differential mass-absorption coefficient for rigidities between 2 and 15 GeV/c for IGY-type neutron monitors at sea level and at 500 mm Hg pressure altitude has been calculated from the variation of the neutron-monitor intensity and mass-absorption coefficient with cutoff rigidity. Combined with six sea-level surveys of neutron-monitor intensity between 1954 and 1962, and assuming no time variation in the neutron-monitor mass-absorption coefficient above 15 GeV/c cutoff, the calculated differential mass-absorption coefficient implies a solar-cycle variation of about 0.04%/mm Hg at 2 GeV/c cutoff rigidity at sea level.

On the nature of some anomalies in the cosmic-ray distribution

1968 ◽  
Vol 46 (10) ◽  
pp. S614-S616 ◽  
Author(s):  
N. P. Chirkov ◽  
G. F. Krymsky ◽  
A. I. Kuzmin
Keyword(s):  
Magnetic Field ◽  
Diurnal Variation ◽  
Interplanetary Magnetic Field ◽  
Equatorial Plane ◽  
Geomagnetic Field ◽  
Cosmic Ray ◽  
Neutron Monitors ◽  
Vector Method ◽  
Worldwide Network ◽  
Northern And Southern Hemispheres

Diurnal and semidiurnal variations of the data from the worldwide network of neutron monitors during 1958 are analyzed using the receiving-vector method. It is shown that there exists an "antisymmetric" diurnal variation, i.e., a variation with opposite phases in the northern and southern hemispheres. After correction for the distortion due to the geomagnetic field, it is found that this variation has an amplitude of 0.03% and an hour of maximum at 21.5 hours in the northern hemisphere. If the variation is due to cosmic-ray screening in the interplanetary magnetic field, this field must have a slope of 7° with respect to the solar equatorial plane.

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.

scholarly journals The Upper Limiting Primary Rigidity of the Cosmic Ray Solar Anisotropy

1965 ◽  
Vol 18 (5) ◽  
pp. 451 ◽  
Author(s):  
RM Jacklyn ◽  
JE Humble
Keyword(s):  
Diurnal Variation ◽  
Sea Level ◽  
Free Space ◽  
Daily Variation ◽  
Cosmic Ray ◽  
Neutron Monitors ◽  
Annual Average ◽  
Average Value

A method of determining the upper limiting rigidity of the solar diurnal variation of the cosmic ray primaries in free space is described. It involves a comparision of the response to the anisotropy of neutron monitors at sea level and of meson telescopes underground. Making use of the model for the free-space first harmonic proposed by Radio, McCracken, and Venkatesan, the annual average value for the upper limiting rigidity (Ru) in 1958 is estimated to have been 95 GV with an error of estimate of about 10-20 GV. Changes in the observed annual mean daily variation between 1958 and 1962 indicate that Ru may have decreased by about 20-40 GV over this period, but a more refined analysis is needed to confirm this.

scholarly journals A Study on Diurnal Variation of Cosmic Ray Flux using Daejeon and Jang Bogo Neutron Monitors

2017 ◽  
Author(s):  
Jongil Jung ◽  
Suyeon Oh ◽  
Yu Yi ◽  
Paul Evenson ◽  
Roger Pyle ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Cosmic Ray ◽  
Neutron Monitors ◽  
Cosmic Ray Flux

scholarly journals Decadal trends in the diurnal variation of galactic cosmic rays observed using neutron monitor data

2017 ◽  
Vol 35 (4) ◽  
pp. 825-838 ◽  
Author(s):  
Simon Thomas ◽  
Mathew Owens ◽  
Mike Lockwood ◽  
Chris Owen
Keyword(s):  
Phase Change ◽  
Diurnal Variation ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
Galactic Cosmic Rays ◽  
Energetic Particles ◽  
Magnetic Polarity ◽  
Neutron Monitors ◽  
Neutron Monitor Data ◽  
Monitor Data

Abstract. The diurnal variation (DV) in galactic cosmic ray (GCR) flux is a widely observed phenomenon in neutron monitor data. The background variation considered primarily in this study is due to the balance between the convection of energetic particles away from the Sun and the inward diffusion of energetic particles along magnetic field lines. However, there are also times of enhanced DV following geomagnetic disturbances caused by coronal mass ejections or corotating interaction regions. In this study we investigate changes in the DV over four solar cycles using ground-based neutron monitors at different magnetic latitudes and longitudes at Earth. We divide all of the hourly neutron monitor data into magnetic polarity cycles to investigate cycle-to-cycle variations in the phase and amplitude of the DV. The results show, in general, a similarity between each of the A < 0 cycles and A > 0 cycles, but with a phase change between the two. To investigate this further, we split the neutron monitor data by solar magnetic polarity between times when the dominant polarity was either directed outward (positive) or inward (negative) at the northern solar pole. We find that the maxima and minima of the DV changes by, typically, 1–2 h between the two polarity states for all non-polar neutron monitors. This difference between cycles becomes even larger in amplitude and phase with the removal of periods with enhanced DV caused by solar wind transients. The time difference between polarity cycles is found to vary in a 22-year cycle for both the maximum and minimum times of the DV. The times of the maximum and minimum in the DV do not always vary in the same manner between A > 0 and A < 0 polarity cycles, suggesting a slight change in the anisotropy vector of GCRs arriving at Earth between polarity cycles. Polar neutron monitors show differences in phase between polarity cycles which have asymptotic directions at mid-to-high latitudes. All neutron monitors show changes in the amplitude of the DV with solar polarity, with the amplitude of the DV being a factor of 2 greater in A < 0 cycles than A > 0 cycles. In most cases the change in timing of the maximum /minimum is greatest with the stations' geomagnetic cut-off rigidity shows little variation in the DV phase with latitude. We conclude that the change in the DV with the dominant solar polar polarity is not as simple as a phase change, but rather an asymmetric variation which is sensitive to the neutron monitor's asymptotic viewing direction.

scholarly journals Galactic cosmic ray decreases associated with non-interacting magnetic clouds in the 23rd solar cycle

2013 ◽  
Vol 8 (S300) ◽  
pp. 483-484
Author(s):  
J. J. Masías-Meza ◽  
S. Dasso
Keyword(s):  
Solar Cycle ◽  
Cosmic Ray ◽  
Total Sample ◽  
Magnetic Clouds ◽  
Neutron Monitors ◽  
Interplanetary Coronal Mass Ejections ◽  
23Rd Solar Cycle ◽  
Preliminary Study ◽  
Galactic Cosmic Ray ◽  
Selection Of

AbstractSudden Galactic Cosmic Ray (GCR) intensity decreases are related to the passage of Interplanetary Coronal Mass Ejections (ICMEs). These phenomena are also known as Forbush Decreases (FDs). The deepest FDs are associated with the passage of Magnetic Clouds (MCs). In this preliminary study we select “non-interacting” MCs associated with FDs observed from ground Neutron Monitors in the period 1996-2009, with the aim of reducing the complexity and the number of parameters involved in the GCR-MC interactions. We introduce a method to determine properties of the “ejecta component” of the FD. We analyze properties of the ejecta component in combination with properties of MCs. From the resulting selection of events, we find that those FDs containing ejecta components show stronger correlations with MC parameters than our total sample of events.

scholarly journals Cosmic ray sidereal diurnal variation of galactic origin observed by neutron monitors

1983 ◽  
Vol 31 (11) ◽  
pp. 1269-1278 ◽  
Author(s):  
K. Nagashima ◽  
Y. Ishida ◽  
S. Mori ◽  
I. Morishita
Keyword(s):  
Diurnal Variation ◽  
Cosmic Ray ◽  
Neutron Monitors
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