Observation of solar modulation of cosmic-ray nuclei

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K03982
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
• Research Institution: Hirosaki University
• Principal Investigator: Ichimura Masakatsu 弘前大学, 理工学研究科, 教授 (20232415)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 太陽変調 / 原子核 / 地磁気効果

Outline of Final Research Achievements

This study aims to obtain the time variation of the intensity of the cosmic ray nuclei, which is necessary for a detailed investigation of cosmic ray propagation processes within the heliosphere. For this purpose, we have developed a method for calculating the absolute intensity of low-energy cosmic ray nuclei using the geomagnetic effect and applied it to the observed data by the CALET experiment, then the absolute intensity of iron nuclei has been obtained. This result showed a good agreement with the other experimental result. It is demonstrating that the method established in this study is enough effective for the aim.

Free Research Field

宇宙線物理学

Academic Significance and Societal Importance of the Research Achievements

太陽磁気圏で宇宙線粒子のドリフトや拡散の様子が太陽の異なるフェイズでどのように変化するのかなど、太陽圏での宇宙線伝播を理解するためには宇宙空間での継続的な観測データが重要となる。また、地球を取り巻く地球磁気圏、太陽磁気圏内の宇宙線のふるまいは太陽活動と直結しており、これを常時観測することは太陽フレアや磁気嵐など地球の通信網や宇宙空間での人類の活動に影響を与える現象を理解し予測することにもつながっている。