Cosmic-Ray Short Burst Observed with the Global Muon Detector Network (GMDN) on 2015 June 22

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Munakata, K. ^[1] ; Kozai, M. ^[2] ; Evenson, P. ^{[3, 4]} ; Kuwabara, T. ^{[3, 4]} ; Kato, C. ^[1] ; Tokumaru, M. ^[5] ; Rockenbach, M. ^[6] ; Dal Lago, A. ^[6] ; de Mendonca, R. R. S. ^{[6, 7]} ; Braga, C. R. ^[6] ; Schuch, N. J. ^[8] ; Al Jassar, H. K. ^[9] ; Sharma, M. M. ^[9] ; Duldig, M. L. ^[10] ; Humble, J. E. ^[10] ; Sabbah, I. ^[11] ; Kota, J. ^[12]

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^[1] Shinshu Univ, Dept Phys, Matsumoto, Nagano 3908621 - Japan

^[2] Japan Aerosp Explorat Agcy ISAS JAXA, Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2525210 - Japan

^[3] Univ Delaware, Bartol Res Inst, Newark, DE 19716 - USA

^[4] Univ Delaware, Dept Phys & Astron, Newark, DE 19716 - USA

^[5] Nagoya Univ, Inst Space Earth Environm Res, Nagoya, Aichi 4648601 - Japan

^[6] Natl Inst Space Res INPE, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[7] Chinese Acad Sci, Natl Space Sci Ctr NSSC, State Key Lab Space Weather, 1 Nanertiao, Beijing 100190 - Peoples R China

^[8] Southern Reg Space Res Ctr CRS INPE, POB 5021, BR-97110970 Santa Maria, RS - Brazil

^[9] Kuwait Univ, Dept Phys, POB 5969, Safat 13060 - Kuwait

^[10] Univ Tasmania, Sch Nat Sci, Hobart, Tas 7001 - Australia

^[11] Publ Author Appl Educ & Training, Coll Hlth Sci, Dept Nat Sci, Kuwait 72853 - Kuwait

^[12] Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 87721 - USA

• Tipo de documento: Artigo Científico
• Fonte: ASTROPHYSICAL JOURNAL; v. 862, n. 2 AUG 1 2018.
• Citações Web of Science: 1

Resumo

We analyze the short cosmic-ray intensity increase ({''}cosmic-ray burst{''}: CRB) on 2015 June 22 utilizing a global network of muon detectors and derive the global anisotropy of cosmic-ray intensity and the density (i.e., the omnidirectional intensity) with 10 minute time resolution. We find that the CRB was caused by a local density maximum and an enhanced anisotropy of cosmic rays, both of which appeared in association with Earth's crossing of the heliospheric current sheet (HCS). This enhanced anisotropy was normal to the HCS and consistent with a diamagnetic drift arising from the spatial gradient of cosmic-ray density, which indicates that cosmic rays were drifting along the HCS from the north of Earth. We also find a significant anisotropy along the HCS, lasting a few hours after the HCS crossing, indicating that cosmic rays penetrated into the inner heliosphere along the HCS. Based on the latest geomagnetic field model, we quantitatively evaluate the reduction of the geomagnetic cutoff rigidity and the variation of the asymptotic viewing direction of cosmic rays due to a major geomagnetic storm that occurred during the CRB and conclude that the CRB is not caused by the geomagnetic storm, but by a rapid change in the cosmic-ray anisotropy and density outside the magnetosphere. (AU)

• Processo FAPESP: 14/24711-6 - Estudo conjunto de ejeções coronais de massa e suas estruturas correspondentes nas vizinhanças da Terra
• Beneficiário: Carlos Roberto Braga
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado