scholarly journals Galactic Anisotropy of Cosmic Ray Intensity Observed by an Air Shower Experiment

2006 ◽  
Vol 23 (3) ◽  
pp. 129-134
Author(s):  
Mahmud Bahmanabadi ◽  
Mehdi Khakian Ghomi ◽  
Farzaneh Sheidaei ◽  
Jalal Samimi
Keyword(s):  
Daily Variation ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Extensive Air Shower ◽  
Air Shower ◽  
The Earth ◽  
The Galaxy ◽  
Unidirectional Anisotropy ◽  
Galactic Cosmic Ray ◽  
Shower Array

AbstractWe have monitored multi-TeV cosmic rays by a small air shower array in Tehran (35°43′ N, 51°20′ E, 1200 m = 890 g cm−2). More than 1.1 × 106 extensive air shower events were recorded. These observations enabled us to analyse sidereal variation of the galactic cosmic ray intensity. The observed sidereal daily variation is compared to the expected variation which includes the Compton–Getting effect due to the motion of the earth in the Galaxy. In addition to the Compton–Getting effect, an anisotropy has been observed which is due to a unidirectional anisotropy of cosmic ray flow along the Galactic arms.

scholarly journals Large-Scale Sidereal Anisotropy of Galactic Cosmic-Ray Intensity Observed by the Tibet Air Shower Array

2005 ◽  
Vol 626 (1) ◽  
pp. L29-L32 ◽  
Author(s):  
M. Amenomori ◽  
S. Ayabe ◽  
S. W. Cui ◽  
Danzengluobu ◽  
L. K. Ding ◽  
...  
Keyword(s):  
Large Scale ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Air Shower ◽  
Galactic Cosmic Ray ◽  
Shower Array ◽  
Sidereal Anisotropy ◽  
Air Shower Array

Sidereal daily variation of ∼10 TeV cosmic-ray intensity observed by the Tibet air shower array

1999 ◽  
Vol 23 (3) ◽  
pp. 599-602 ◽  
Author(s):  
K Munakata ◽  
T Hara ◽  
S Yasue ◽  
C Kato ◽  
D.L Hall ◽  
...  
Keyword(s):  
Daily Variation ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Air Shower ◽  
Shower Array ◽  
Air Shower Array

μNet: Towards the first array of educational air shower detectors in Greece

2020 ◽  
Vol 35 (34n35) ◽  
pp. 2044022
Author(s):  
Michael Petropoulos ◽  
Antonios Leisos ◽  
Apostolos Tsirigotis
Keyword(s):  
High School Students ◽  
Geographical Area ◽  
Cosmic Ray ◽  
Pilot Phase ◽  
School Students ◽  
Extensive Air Shower ◽  
Active Involvement ◽  
Air Shower ◽  
School Laboratory ◽  
Shower Array

We report on the design and the pilot phase of the [Formula: see text]Net project that aims for the active involvement of Greek high school students in the experimental procedures of astroparticle physics and especially in cosmic ray physics. Through the anticipated educational program, the students from the geographical area of Peloponnese will construct and operate educational cosmic ray telescopes deployed at their school laboratory and/or perform distant educational activities utilizing the extensive air shower array and the relevant remotely operated experimental setups of the Hellenic Open University Physics Laboratory.

Time variations of directional cosmic ray intensity at low latitudes - III. Interpretation of solar daily variation and changes of east-west asymmetry

1961 ◽  
Vol 263 (1312) ◽  
pp. 127-135 ◽  
Keyword(s):  
Energy Spectrum ◽  
Interplanetary Space ◽  
Daily Variation ◽  
Cosmic Ray ◽  
Local Source ◽  
Cosmic Ray Intensity ◽  
The Earth ◽  
Low Latitudes ◽  
Time Variations ◽  
East West

The daily variation of cosmic ray intensity at low latitudes can under certain conditions be associated with an anisotropy of primary radiation. During 1957-8, this anisotropy had an energy spectrum of variation of the form aϵ -0.8±0.3 and corresponded to a source situated at an angle of 112 ± 10° to the left of the earth-sun line. The daily variation which can be associated with a local source situated along the earth-sun line has an energy spectrum of variation of the form aϵ 0 . Increases in east-west asymmetry and the associated daily variation for east and west directions can be explained by the acceleration of cosmic ray particles crossing beams of solar plasma in the neighbourhood of the earth. For beams of width 5 x 10 12 cm with a frozen magnetic field of the order of 10 -4 G, a radial velocity of about 1.5 x 108 cm/s is required. The process is possible only if the ejection of beams takes place in rarefied regions of inter­ planetary space which extend radially over active solar regions. An explanation of Forbush, type decreases observed at great distances from the earth requires similar limitation on the plasma density and conductivity of regions of interplanetary space. The decrease of east-west asymmetry associated with world-wide decreases of intensity and with SC magnetic storms is consistent with a screening of the low-energy cosmic ray particles due to magnetic fields in plasma clouds.

scholarly journals Northern Sky Galactic Cosmic Ray Anisotropy between 10 and 1000 TeV with the Tibet Air Shower Array

2017 ◽  
Vol 836 (2) ◽  
pp. 153 ◽  
Author(s):  
M. Amenomori ◽  
X. J. Bi ◽  
D. Chen ◽  
T. L. Chen ◽  
W. Y. Chen ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Air Shower ◽  
Galactic Cosmic Ray ◽  
Shower Array ◽  
Air Shower Array

scholarly journals On the Solar Cycle Variation of the Solar Diurnal Anisotropy of Multi-TeV Cosmic-ray Intensity Observed with the Tibet Air Shower Array

2019 ◽  
Vol 208 ◽  
pp. 08012
Author(s):  
M. Amenomori ◽  
X. J. Bi ◽  
D. Chen ◽  
T. L. Chen ◽  
W. Y. Chen ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Cosmic Ray ◽  
Local Solar Time ◽  
Solar Cycle Variation ◽  
Cosmic Ray Intensity ◽  
Air Shower ◽  
23Rd Solar Cycle ◽  
Diurnal Anisotropy ◽  
Shower Array ◽  
Air Shower Array

We analyze the temporal variation of the solar diurnal anisotropy of the multi-TeV cosmic-ray intensity observed with the Tibet air shower array from 2000 to 2009, covering the maximum and minimum of the 23rd solar cycle. We comfirm that a remarkable additional anisotropy component is superposed on the Compton-Getting anisotropy at 4.0 TeV, while its amplitude decreases at higher energy regions. In constrast to the additional anisotropy reported by the Matsushiro experiment at 0.6 TeV, we find the residual component measured by Tibet at multi-TeV energies is consistent with being stable, with a fairly constant amplitude of 0.041% ± 0.003% and a phase at around 07.17 ± 00.16 local solar time at 4.0 TeV. This suggests the additional anisotropy observed by the Tibet experiment could result from mechanisms unrelated to solar activities.

Semidiurnal Anisotropy of Galactic Cosmic Ray Intensity

1971 ◽  
Vol 49 (1) ◽  
pp. 34-48 ◽  
Author(s):  
G. Subramanian
Keyword(s):  
Energy Spectrum ◽  
Counting Rate ◽  
Interplanetary Space ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
The Earth ◽  
Positive Exponent ◽  
Semidiurnal Variation ◽  
Using Data ◽  
Galactic Cosmic Ray

The semidiurnal variation of galactic cosmic ray intensity is investigated using data from mainly high counting rate neutron and meson monitors during 1964–1968. It is shown that in order to explain the observed semidiurnal variation it is necessary that an anisotropy of cosmic ray intensity be present in interplanetary space. The energy spectrum and the asymptotic latitude dependence of the anisotropy are then determined. The energy spectrum has a positive exponent close to + 1 for the power law in energy. The strength of the anisotropy decreases more rapidly than cosλ with increasing asymptotic latitude λ, both cos2λ and cos3λ being acceptable. The distribution of cosmic ray intensity in the range of heliolatitudes ± 7.25° at the orbit of the earth, obtained using data from the Ottawa neutron monitor, does not support the explanation of the semidiurnal variation based on the models of Subramanian and Sarabhai or Lietti and Quenby.

THE ONSET TIMES OF FORBUSH-TYPE COSMIC RAY INTENSITY DECREASES

1959 ◽  
Vol 37 (9) ◽  
pp. 970-982 ◽  
Author(s):  
A. G. Fenton ◽  
K. G. McCracken ◽  
D. C. Rose ◽  
B. G. Wilson
Keyword(s):  
Daily Variation ◽  
Cosmic Ray ◽  
Consistent Pattern ◽  
Maximum Sensitivity ◽  
Geomagnetic Disturbances ◽  
Cosmic Ray Intensity ◽  
Early Stages ◽  
The Earth ◽  
Directional Anisotropy ◽  
Quiet Day

The onset times of a number of Forbush-type decreases observed at four widely spaced stations are compared, and it is shown that appreciable differences occur. The stations selected were Hobart, Mawson, Ottawa, and Sulphur Mountain. It was found that a consistent pattern is obtained for the events studied when the onset times are plotted as a function of the direction of maximum sensitivity of the recorders relative to the earth-sun line. This is interpreted as being due to a directional anisotropy that exists in the mechanism producing the decreases, at least in the early stages. The depression occurs first for particles arriving from directions between 30° and 120° west of the earth–sun line. The relation between these observations and geomagnetic disturbances and the quiet-day daily variation is discussed.

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