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North-south anisotropy of galactic cosmic rays observed with the Global Muon Detector Network (GMDN)
Citation
Munakata, K and Kozai, M and Kato, C and Kuwabara, T and Rockenbach, M and Dal Lago, A and Schuch, NJ and Al Jassar, HK and Sharma, MM and Duldig, ML and Humble, JE and Bieber, JW and Evenson, P and Sabbah, I and Tokumaru, M, North-south anisotropy of galactic cosmic rays observed with the Global Muon Detector Network (GMDN), Proceedings of Science, 30 July - 06 August, The Hague, Netherlands, pp. 1-7. ISSN 1824-8039 (2015) [Non Refereed Conference Paper]
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Abstract
We analyze the north-south anisotropy (NSA) of galactic cosmic rays observed with the GMDN
on an hourly basis and compare with the anisotropy derived from the GG-component of a large
multidirectional muon detector at Nagoya, Japan. The NSA is a component of the three dimensional
anisotropy vector parallel to the Earth’s rotation axis. We find a significant seasonal variation
of the NSA from the GG-component indicating the influence of the anisotropy component
in the ecliptic plane to the NSA. We calculate the average and standard deviation of daily mean
NSAs in the "toward" (T) and "away" (A) IMF sectors separately in each Carrington Rotation
between December 1993 and November 2014. It is confirmed that the temporal variations of the
NSA observed with the GMDN and GG-component are consistent with each other, as reported
earlier. We find the T-A separation between average NSAs in T and A sectors shows a long-term
variation with minima (maxima) around the solar activity minima (maxima). The standard deviation
in each rotation also shows a similar long-term variation, keeping the ratio of T-A separation
to the standard deviation roughly constant thorough out an entire period of analysis. We discuss
this in relation with the "success rate" which is introduced as a parameter indicating to what extent
we can infer the IMF sector polarity from the sign of the observed NSA.
Item Details
| Item Type: | Non Refereed Conference Paper |
|---|---|
| Keywords: | cosmic rays, modulation, north-south anisotropy |
| Research Division: | Physical Sciences |
| Research Group: | Astronomical and Space Sciences |
| Research Field: | High Energy Astrophysics; Cosmic Rays |
| Objective Division: | Expanding Knowledge |
| Objective Group: | Expanding Knowledge |
| Objective Field: | Expanding Knowledge in the Physical Sciences |
| UTAS Author: | Duldig, ML (Dr Marc Duldig) |
| UTAS Author: | Humble, JE (Dr John Humble) |
| ID Code: | 110300 |
| Year Published: | 2015 |
| Deposited By: | Mathematics and Physics |
| Deposited On: | 2016-07-23 |
| Last Modified: | 2016-08-05 |
| Downloads: | 0 |
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