[P-EM09] Space Weather and Space Climate

[PEM09-24] Cosmic ray variation at the Earth caused by flank-side or backside coronal mass ejections

*林 優希¹、加藤 千尋¹、宗像 一起¹、増田 吉起¹、片岡 龍峰²、門倉 昭^2,3、小財 正義³、三宅 晶子⁴、岩井 一正⁵、Mendonça Rafael⁶、Braga Carlos⁷、Echer Ezequiel ⁶、Dal Lago Alisson⁶、Rockenbach M.⁶、Shcuch N.⁶、Al Jassar H.⁸、Sharma Madan⁸、Bageston José⁶、Sabbah Ismail¹¹、Duldig Marc⁹、Humble J.⁹、Evenson Paul¹⁰ (1.信州大学、2.国立極地研究所、3.データサイエンス共同利用基盤施設、4.茨城工業高等専門学校、5.名古屋大学宇宙地球環境研究所、6.National Institute for Space Research、7.George Mason University、8.Kuwait University、9.University of Tasmania、10.University of Delaware、11. College of Technological Studies, Public Authority for Applied Education and Training)

キーワード：側面または背面のCME、銀河宇宙線強度変動

The galactic cosmic-ray (GCR) intensity at Earth sometimes shows transient variations related to solar activity, such as coronal mass ejections (CMEs). We have observed the transient GCR intensity variations using the Global Muon Detector Network (GMDN) for decades. The largest-amplitude transient GCR variations are the so-called Forbush decrease events, which are caused by fast CMEs coming to Earth. However, the possible GCR variations associated with flank-side or backside CMEs have been poorly understood. We report the initial analysis of such candidate events, including January and July 2012 CME events, to discuss the possibility of diagnosing the meso-scale cosmic ray distributions in the inner heliosphere.