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.

Cosmic Ray Intensity Decrease of 23 September, 1966

1971 ◽  
Vol 49 (2) ◽  
pp. 265-269 ◽  
Author(s):  
U. D. Desai
Keyword(s):  
Magnetic Storm ◽  
Forbush Decrease ◽  
Cosmic Ray ◽  
The Sun ◽  
Neutron Monitors ◽  
Magnetic Field Data ◽  
Cosmic Ray Intensity ◽  
Diurnal Anisotropy ◽  
Shadow Cast ◽  
Two Phases

Earlier studies have interpreted the Forbush decrease of 23 September 1966 in terms of two phases; an initial predecrease and a later worldwide decrease. This interpretation precluded the possibility of correlation with a concurrent magnetic storm and led to an explanation of the predecrease (Mathews et al. 1968) in terms of a shadow cast by a distant plasma cloud approaching from a direction 85° to the west of the sun–earth line.In the present study, particle and magnetic field data from satellite-borne detectors and ground-based neutron monitors clearly show the onset of the Forbush decrease coincident with the SSC magnetic storm. It is pointed out that the Forbush decrease arises from a corotating shock front approaching from the east of the sun–earth line and is not associated with any solar flare effect. Further, the increases observed by the various neutron monitors 9 h after the onset of the Forbush decrease are interpreted to be an enhancement of the diurnal anisotropy. An example of an increase in intensity in the IMP 3 detector arising from electron contributions is also pointed out.

scholarly journals Modulation effect of magnetic corotating trap on 27-day cosmic ray variation in November–December 2014

2019 ◽  
Vol 5 (1) ◽  
pp. 11-13
Author(s):  
Валерий Сдобнов ◽  
Valeriy Sdobnov ◽  
Марина Кравцова ◽  
Marina Kravtsova ◽  
Сергей Олемской ◽  
...  
Keyword(s):  
Energy Loss ◽  
Interplanetary Space ◽  
Intensity Variation ◽  
Cosmic Ray ◽  
Energy Losses ◽  
The Sun ◽  
Modulation Effect ◽  
Neutron Monitors ◽  
Worldwide Network ◽  
Determining Factor

We study the 27-day cosmic-ray (CR) intensity variation occurring in November–December 2014, using ground-based measurements from the worldwide network of neutron monitors and GOES-15 satellites. A determining factor in the considerable difference between amplitudes of the 27-day CR variation in November–December 2014 is shown to be significant changes in energy losses taking place when particles move in regular heliospheric electromagnetic fields. In this period, there was a long-living corotating trap produced by a vast coronal hole in the south of the Sun in interplanetary space. Configuration of this trap induced the energy loss of ~3–20 GeV CRs, due to which ground-based neutron monitors recorded an abnormally large amplitude of the 27-day variation.

scholarly journals Modulation effect of magnetic corotating trap on 27-day cosmic ray variation in November–December 2014

2019 ◽  
Vol 5 (1) ◽  
pp. 13-16
Author(s):  
Валерий Сдобнов ◽  
Valeriy Sdobnov ◽  
Марина Кравцова ◽  
Marina Kravtsova ◽  
Сергей Олемской ◽  
...  
Keyword(s):  
Energy Loss ◽  
Interplanetary Space ◽  
Intensity Variation ◽  
Cosmic Ray ◽  
Energy Losses ◽  
The Sun ◽  
Modulation Effect ◽  
Neutron Monitors ◽  
Worldwide Network ◽  
Determining Factor

We study the 27-day cosmic-ray (CR) intensity variation occurring in November–December 2014, using ground-based measurements from the worldwide network of neutron monitors and GOES-15 satellites. A determining factor in the considerable difference between amplitudes of the 27-day CR variation in November–December 2014 is shown to be significant changes in energy losses taking place when particles move in regular heliospheric electromagnetic fields. In this period, there was a long-living corotating trap produced by a vast coronal hole in the south of the Sun in interplanetary space. Configuration of this trap induced the energy loss of ~3–20 GeV CRs, due to which ground-based neutron monitors recorded an abnormally large amplitude of the 27-day variation.

scholarly journals The primary cosmic-ray electron spectrum in the energy range from 300 MeV to 4 BeV from 1964 to 1966

1968 ◽  
Vol 46 (10) ◽  
pp. S892-S895 ◽  
Author(s):  
Jacques L'heureux ◽  
Peter Meyer
Keyword(s):  
Energy Spectrum ◽  
Electron Spectrum ◽  
Intensity Variation ◽  
Cosmic Ray ◽  
Primary Electron ◽  
Counter Telescope ◽  
Improved Accuracy ◽  
Primary Electrons

Measurements of the primary electron spectrum were made during the summers of 1964, 1965, and 1966 using a balloon-borne counter telescope flown from Fort Churchill, Manitoba. Several balloon flights were carried out in each year in order to eliminate short-term intensity variations. This paper addresses itself to two questions: (1) the determination of the energy spectrum of primary electrons in the energy interval from 300 MeV to 4 BeV; and (2) the long-term intensity variations of the primary electron flux from 1964 through 1966. The energy spectrum was determined with improved accuracy in 1966 and agrees with our previous results. Comparison of the electron spectra obtained in 1964, 1965, and 1966 shows that, within the errors of our measurements, no long-term intensity variation existed. The upper limit for the change of flux with respect to 1965 amounts to 20% in all energy intervals studied.[Formula: see text]

scholarly journals Latitudinal and longitudinal dependence of the cosmic ray diurnal anisotropy during 2001–2014

2016 ◽  
Vol 34 (11) ◽  
pp. 1053-1068 ◽  
Author(s):  
Anastasia Tezari ◽  
Helen Mavromichalaki ◽  
Dimitrios Katsinis ◽  
Anastasios Kanellakopoulos ◽  
Sofia Kolovi ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
Longitudinal Distribution ◽  
Solar Cycles ◽  
Field Polarity ◽  
Monthly Basis ◽  
Cosmic Ray Intensity ◽  
Asymptotic Cones ◽  
Diurnal Anisotropy

Abstract. The diurnal anisotropy of cosmic ray intensity for the time period 2001 to 2014 is studied, covering the maximum and the descending phase of solar cycle 23, the minimum between solar cycles 23 and 24, and the ascending phase and maximum of solar cycle 24. Cosmic ray intensity data from 11 neutron monitor stations located at different places around the Northern Hemisphere obtained from the high-resolution Neutron Monitor Database (NMDB) were used. Special software was developed for the calculations of the amplitude and the phase of the diurnal anisotropy vectors on annual and monthly basis using Fourier analysis and for the creation of the harmonic dial diagrams. The geomagnetic bending for each station was taken into account in our calculations determined from the asymptotic cones of each station via the Tsyganenko96 (Tsyganenko and Stern, 1996) magnetospheric model. From our analysis, it was resulted that there is a different behavior of the diurnal anisotropy vectors during the different phases of the solar cycles depending on the solar magnetic field polarity. The latitudinal and longitudinal distribution of the cosmic ray diurnal anisotropy was also examined by grouping the stations according to their geographic coordinates, and it was shown that diurnal variation is modulated not only by the latitude but also by the longitude of the stations. The diurnal anisotropy during strong events of solar and/or cosmic ray activity is discussed.

Small-scale cosmic-ray fluctuations and their association with recurrent phenomena, October 1965 through April 1966

1968 ◽  
Vol 46 (10) ◽  
pp. S866-S870 ◽  
Author(s):  
F. Bachelet ◽  
E. Dyring ◽  
N. Iucci ◽  
G. Villoresi
Keyword(s):  
Power Spectrum ◽  
Diurnal Variation ◽  
Spectrum Analysis ◽  
High Latitude ◽  
Cosmic Ray ◽  
Power Spectrum Analysis ◽  
Small Scale ◽  
High Latitudes ◽  
Neutron Monitors

A method is developed for separating the diurnal variation from cosmic-ray data recorded by NM64 neutron monitors at high latitudes. It utilizes the negligible diurnal variation at the Alert station, which is verified by power spectrum analysis. The method offers the development of a "universal high-latitude diurnal wave" on a day-to-day basis, taking into account the asymptotic longitude differences between the stations.The period 15 October 1965 to 30 April 1966 is studied in connection with the space measurements of Pioneer VI.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

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