98 citations · 899 across the 28 of their papers we have counts for
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The Earliest Candidates of Auroral Observations in Assyrian Astrological Reports: Insights on Solar Activity around 660 BCE
Hisashi Hayakawa, Yasuyuki Mitsuma, Yusuke Ebihara +1
Auroral records found in historical archives and cosmogenic isotopes found in natural archives have served as sound proxies of coronal mass ejections (CMEs) and solar energetic par…
Temporal and Spatial Evolutions of a Large Sunspot Group and Great Auroral Storms around the Carrington Event in 1859
Hisashi Hayakawa, Yusuke Ebihara, David M. Willis +10
The Carrington event is considered to be one of the most extreme space weather events in observational history within a series of magnetic storms caused by extreme interplanetary c…
Occurrence of Great Magnetic Storms on 6-8 March 1582
Kentaro Hattori, Hisashi Hayakawa, Yusuke Ebihara
Although knowing the occurrence frequency of severe space weather events is important for a modern society, it is insufficiently known due to the lack of magnetic or sunspot observ…
Intense geomagnetic storm during Maunder minimum possibly by a quiescent filament eruption
Hiroaki Isobe, Yusuke Ebihara, Akito D. Kawamura +2
The sun occasionally undergoes the so-called grand minima, in which its magnetic activity, measured by the number of sunspots, is suppressed for decades. The most prominent grand m…
Do the Chinese Astronomical Records Dated AD 776 January 12/13 Describe an Auroral Display or a Lunar Halo? A Critical Re-examination
F. Richard Stephenson, David M. Willis, Hisashi Hayakawa +4
The enhancement of carbon-14 in tree rings around AD 774/775 has generated wide interest in solar activity at that time. The historical auroral records have been examined criticall…
The Celestial Sign in the Anglo-Saxon Chronicle in the 770s: Insights on Contemporary Solar Activity
Hisashi Hayakawa, F. Richard Stephenson, Yuta Uchikawa +5
The anomalous concentration of radiocarbon in 774/775 attracted intense discussion on its origin, including the possible extreme solar event(s) exceeding any events in observationa…