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within Hiroko Miyahara Remove this filter Science, Humanities and Social Sciences, multidisciplinary Remove this filter

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  1. Article

    Open Access

    Gradual onset of the Maunder Minimum revealed by high-precision carbon-14 analyses

    The Sun exhibits centennial-scale activity variations and sometimes encounters grand solar minimum when solar activity becomes extremely weak and sunspots disappear for several decades. Such an extreme weakeni...

    Hiroko Miyahara, Fuyuki Tokanai, Toru Moriya, Mirei Takeyama… in Scientific Reports (2021)

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  2. Article

    Open Access

    Prolonged production of 14C during the ~660 BCE solar proton event from Japanese tree rings

    Annual rings record the intensity of cosmic rays (CRs) that had entered into the Earth’s atmosphere. Several rapid 14C increases in the past, such as the 775 CE and 994CE 14C spikes, have been reported to origina...

    Hirohisa Sakurai, Fuyuki Tokanai, Fusa Miyake, Kazuho Horiuchi… in Scientific Reports (2020)

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