https://doi.org/10.1051/epjconf/201920808012
On the Solar Cycle Variation of the Solar Diurnal Anisotropy of Multi-TeV Cosmic-ray Intensity Observed with the Tibet Air Shower Array
1
Department of Physics, Hirosaki University, Hirosaki 036-8561, Japan
2
Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
3
National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China
4
Department of Mathematics and Physics, Tibet University, Lhasa 850000, China
5
Department of Physics, Hebei Normal University, Shijiazhuang 050016, China
6
Department of Physics, Shandong University, Jinan 250100, China
7
Institute of Modern Physics, SouthWest Jiaotong University, Chengdu 610031, China
8
Faculty of Engineering, Kanagawa University, Yokohama 221-8686, Japan
9
Faculty of Education, Utsunomiya University, Utsunomiya 321-8505, Japan
10
Department of Physics, Konan University, Kobe 658-8501, Japan
11
Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555, Japan
12
Faculty of Engineering, Yokohama National University, Yokohama 240-8501, Japan
13
Department of Physics, Shinshu University, Matsumoto 390-8621, Japan
14
Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582, Japan
15
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Sagamihara 252-5210, Japan
16
National Center for Space Weather, China Meteorological Administration, Beijing 100081, China
17
School of Information Science and Engineering, Shandong Agriculture University, Taian 271018, China
18
University of Chinese Academy of Sciences, Beijing 100049, China
19
National Institute of Informatics, Tokyo 101-8430, Japan
20
Sakushin Gakuin University, Utsunomiya 321-3295, Japan
21
College of Science, China University of Petroleum, Qingdao 266555, China
22
Tokyo Metropolitan College of Industrial Technology, Tokyo 116-8523, Japan
23
Max-Planck-Institut für Physik, Munich D-80805, Germany
24
College of Industrial Technology, Nihon University, Narashino 275-8576, Japan
25
Shonan Institute of Technology, Fujisawa 251-8511, Japan
26
Japan Atomic Energy Agency, Tokai-mura 319-1195, Japan
* e-mail: linyh@ihep.ac.cn ORCID: 0000-0002-1767-6280
Published online: 10 May 2019
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.
© The Authors, published by EDP Sciences, 2019
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
