A cosmic ray density gradient perpendicular to the ecliptic plane

1972 ◽  
Vol 20 (5) ◽  
pp. 791-801 ◽  
Author(s):  
A. Hashim ◽  
M. Bercovitch
Keyword(s):  
Density Gradient ◽  
Cosmic Ray ◽  
Ecliptic Plane ◽  
Ray Density

The North–South Anisotropy and the Radial Density Gradient of Galactic Cosmic Rays at 1 AU

1995 ◽  
Vol 12 (2) ◽  
pp. 153-158 ◽  
Author(s):  
D. L. Hall ◽  
M. L. Duldig ◽  
J. E. Humble
Keyword(s):  
Cosmic Rays ◽  
Diurnal Variation ◽  
Density Gradient ◽  
Cosmic Ray ◽  
Ecliptic Plane ◽  
Galactic Cosmic Rays ◽  
Radial Density ◽  
Sidereal Time ◽  
Direction Parallel ◽  
The North

AbstractThe radial density gradient (Gr) of Galactic cosmic rays in the ecliptic plane points outward from the Sun. This indicates an increasing density of cosmic ray particles beyond the Earth’s orbit. Due to this gradient and the direction of the Sun’s interplanetary magnetic field (IMF) above and below the IMF wavy neutral sheet, there exists an anisotropic flow of cosmic ray particles approximately perpendicular to the ecliptic plane (i.e. in the direction parallel to BIMF × Gr). This effect is called the north–south anisotropy (ξNS) and manifests as a diurnal variation in sidereal time in the particle intensity recorded by a cosmic ray detector. By analysing the yearly averaged sidereal diurnal variation recorded by five neutron monitors and six muon telescopes from 1957 to 1990, we have deduced probable values of the average rigidity spectrum and magnitude of ξNS. Furthermore, we have used determined yearly amplitudes of ξNS to infer the magnitude of Gr for particles with rigidities in excess of 10 GV.

Energy Changes of Cosmic Rays

1978 ◽  
Vol 3 (3) ◽  
pp. 233-234
Author(s):  
L. J. Gleeson ◽  
G. M. Webb
Keyword(s):  
Cosmic Rays ◽  
Solar System ◽  
Density Gradient ◽  
Cosmic Ray ◽  
Integral Form ◽  
Rate Of Change ◽  
Number Density ◽  
Ray Density ◽  
The Mean

Recently (Gleeson (1972), Quenby (1973), Gleeson and Webb (1974, 1978)) it has been shown that the mean rate of change of momentum of cosmic rays reckoned for a volume fixed in the solar system iswhere G = (1/Up)(∂Up/∂r)si the cosmic-ray density gradient with Up, the differential number density with respect to momentum p at position r. (cf also the integral form of (1) by Jokipii and Parker 1967).

The daily-variation second harmonic and a cosmic-ray intensity gradient perpendicular to the ecliptic

1968 ◽  
Vol 46 (10) ◽  
pp. S942-S945 ◽  
Author(s):  
B. Lietti ◽  
J. J. Quenby
Keyword(s):  
Daily Variation ◽  
Second Harmonic ◽  
Cosmic Ray ◽  
Ecliptic Plane ◽  
Positive Power ◽  
Cosmic Ray Intensity ◽  
Parallel Diffusion ◽  
Ray Density ◽  
Field Lines ◽  
Rigidity Dependence

Since the spiral interplanetary magnetic field is expected to be much less tightly wound at high solar latitudes, galactic particles arriving along the sun's polar field lines may suffer much less modulation than those arriving in the ecliptic plane. Hence a rising cosmic-ray density gradient is expected away from the ecliptic which will give rise to a second harmonic in the cosmic-ray daily variation with maxima at right angles to the spiral field direction. Two extreme models for the gradient are considered: one for predominantly particle diffusion along the field lines and the other when the diffusion is all perpendicular to the lines. Both models give a first positive power of rigidity dependence to the second harmonic in the 1 to 15 GV range with a double amplitude of about 0.05% at 10 GV. This is in rough accord with experimental results, which also can be shown to favor the parallel diffusion model at higher rigidities.

scholarly journals CONSTRAINTS ON THE COSMIC-RAY DENSITY GRADIENT BEYOND THE SOLAR CIRCLE FROMFERMIγ-RAY OBSERVATIONS OF THE THIRD GALACTIC QUADRANT

2010 ◽  
Vol 726 (2) ◽  
pp. 81 ◽  
Author(s):  
M. Ackermann ◽  
M. Ajello ◽  
L. Baldini ◽  
J. Ballet ◽  
G. Barbiellini ◽  
...  
Keyword(s):  
Density Gradient ◽  
Cosmic Ray ◽  
The Third ◽  
Ray Density

scholarly journals ERRATUM: “CONSTRAINTS ON THE COSMIC-RAY DENSITY GRADIENT BEYOND THE SOLAR CIRCLE FROM FERMI γ-RAY OBSERVATIONS OF THE THIRD GALACTIC QUADRANT” (2011, ApJ, 726, 81)

2013 ◽  
Vol 772 (2) ◽  
pp. 154 ◽  
Author(s):  
M. Ackermann ◽  
M. Ajello ◽  
L. Baldini ◽  
J. Ballet ◽  
G. Barbiellini ◽  
...  
Keyword(s):  
Density Gradient ◽  
Cosmic Ray ◽  
The Third ◽  
Ray Density ◽  
Γ Ray

scholarly journals Drift Effects and the Cosmic Ray Density Gradient in a Solar Rotation Period: First Observation with the Global Muon Detector Network (GMDN)

2008 ◽  
Vol 681 (1) ◽  
pp. 693-707 ◽  
Author(s):  
Y. Okazaki ◽  
A. Fushishita ◽  
T. Narumi ◽  
C. Kato ◽  
S. Yasue ◽  
...  
Keyword(s):  
Density Gradient ◽  
Solar Rotation ◽  
Rotation Period ◽  
Cosmic Ray ◽  
Muon Detector ◽  
Ray Density

Evidence for Large Scale Cosmic Ray Electron Gradients in the Galaxy

1976 ◽  
Vol 3 (1) ◽  
pp. 1-6 ◽  
Author(s):  
W. R. Webber
Keyword(s):  
Large Scale ◽  
Spiral Structure ◽  
Cosmic Ray ◽  
Point Sources ◽  
Interstellar Matter ◽  
Interstellar Gas ◽  
The Galaxy ◽  
Ray Density ◽  
Γ Rays ◽  
Γ Ray

In recent years observations of γ-ray emission from the disk of the galaxy have provided a new opportunity for research into the structure of the spiral arms of our own galaxy. In Figure 1 we show a map of the structure of the disk of the galaxy as observed for γ-rays of energy > 100 MeV by the SAS-2 satellite (Fichtel et al. 1975). The angular resolution of these measurements is ~ 3°, and besides two point sources at l = 190° and 265° several features related to the spiral structure of the galaxy are evident in the data. Most of these γ-rays are believed to arise from the decay of π° mesons produced by the nuclear interactions of cosmic rays (mostly protons) with the ambient interstellar gas. As a result, the γ-ray fluxes represent a measure of the line of sight integral of the product of the cosmic ray density NCR and the interstellar matter density N1

Sign in / Sign up

Export Citation Format

Share Document