Fusa Miyake

Fusa Miyake (born 1987) is a cosmic ray physicist at Nagoya University, Japan, whose work measuring isotope abundances led to recognition of so-called Miyake events. These have resulted in reconciling differences between dates from documents and materials such as ice-cores and tree rings.

Scientific career Fusa Miyake gained her doctorate from Nagoya University in 2013 and was then appointed as an assistant professor. In 2017 she was promoted to associate professor in the Division for Cosmic Ray Research within the Space-Earth Environmental Research Division.

Her doctoral research identified events in the wood of long-lived Japanese cedar trees, now called Miyake events, where there are sudden increases in cosmogenic isotopes such as radioactive carbon isotope , and produced by cosmic rays originating from the Sun when large solar flares or eruptions occur. These isotopes can be detected in materials such as tree-rings and ice cores. Although the event was initially proposed to be a signature of an unidentified supernova, it was soon proven to be the discovery of an extreme solar particle event and confirmed independently. As an example, measurements can utilised the carbon in the polymer cellulose extracted from tree-rings formed in individual years to measure abundance of the isotope using accelerator mass spectrometry. Measuring these isotopes in materials that have been independently dated allow the events to be dated with precision. This gives information about the Sun's long-term activity. She identified an event in 775 during her doctoral work, and along with colleagues, has subsequently identified events centred on 993-4 and also 660 and 5480 BCE. By 2023, 6 Miyake events had been identified.