98 citations · 1.3k across the 49 of their papers we have counts for
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The Dalton Minimum and John Dalton's Auroral Observations
Sam M. Silverman, Hisashi Hayakawa
In addition to the regular Schwabe cycles of approximately 11 y, "prolonged solar activity minima" have been identified through the direct observation of sunspots and aurorae, as w…
Cometary records revise Eastern Mediterranean chronology around 1240 CE
Koji Murata, Kohei Ichikawa, Yuri I. Fujii +4
Eirene Laskarina, empress of John III Batatzes of the exiled Byzantine Empire of Nicaea (1204--1261 CE), was an important Eastern Mediterranean figure in the first half of the thir…
The intensity and evolution of the extreme storms in January 1938
Hisashi Hayakawa, Kentaro Hattori, Alexei A. Pevtsov +7
Major solar eruptions occasionally direct interplanetary coronal mass ejections (ICMEs) to Earth and cause significant geomagnetic storms and low-latitude aurorae. While single ext…
The Extreme Space Weather Event in February/March 1941
Hisashi Hayakawa, Sean P. Blake, Ankush Bhaskar +3
Given the infrequency of extreme geomagnetic storms, it is significant to note the concentration of three extreme geomagnetic storms in 1941, whose intensities ranked fourth, twelf…
Reanalyses of the Sunspot Observations of Fogelius and Siverus: Two "Long-Term" Observers during the Maunder Minimum
Hisashi Hayakawa, Tomoya Iju, Shoma Uneme +3
The solar activity during the Maunder Minimum (MM; 1645 -- 1715) has been considered significantly different from the one captured in modern observations, in terms of sunspot group…
Candidate Auroral Observations during the Major Solar-Terrestrial Storm in May 1680: Implication for Space Weather Events during the Maunder Minimum
Hisashi Hayakawa, Kristian Schlegel, Bruno P. Besser +1
The Maunder Minimum (1645-1715) is currently considered the only grand minimum within telescopic sunspot observations since 1610. During this epoch, the Sun was extremely quiet and…
South American auroral reports during the Carrington storm
Hisashi Hayakawa, José R. Ribeiro, Yusuke Ebihara +2
The importance of the investigation of magnetic superstorms is not limited to academic interest, because these superstorms can cause catastrophic impact on the modern civilisation…
Estimating Satellite Orbital Drag During Historical Magnetic Superstorms
Denny M. Oliveira, Eftyhia Zesta, Hisashi Hayakawa +1
Understanding extreme space weather events is of paramount importance in efforts to protect technological systems in space and on the ground. Particularly in the thermosphere, the…
The Solar Corona during the Total Eclipse on 16 June 1806: Graphical Evidence of the Coronal Structure during the Dalton Minimum
Hisashi Hayakawa, Mathew J. Owens, Michael Lockwood +1
Visible coronal structure, in particular the spatial evolution of coronal streamers, provides indirect information about solar magnetic activity and the underlying solar dynamo. Th…
A possible case of sporadic aurora observed at Rio de Janeiro
Denny M. Oliveira, Hisashi Hayakawa, Ankush Bhaskar +2
Being footprints of major magnetic storms and hence major solar eruptions, mid- to low-latitude aurorae have been one of the pathways to understand solar-terrestrial environments.…
Extreme Space Weather Events Recorded in History
Hisashi Hayakawa, Yusuke Ebihara
This section shows an overview of a recent development of the studies on great space weather events in history. Its discussion starts from the Carrington event and compare its inte…
Provenance of the Cross Sign of 806 in the Anglo-Saxon Chronicle: A possible Lunar Halo over Continental Europe?
Yuta Uchikawa, Les Cowley, Hisashi Hayakawa +2
While graphical records of astronomical/meteorological events before telescopic observations are of particular interest, they have frequently undergone multiple copying and may hav…
The Extreme Space Weather Event in 1903 October/November: An Outburst from the Quiet Sun
Hisashi Hayakawa, Paulo Ribeiro, José M. Vaquero +11
While the Sun is generally more eruptive during its maximum and declining phases, observational evidence shows certain cases of powerful solar eruptions during the quiet phase of t…
Thaddäus Derfflinger's sunspot observations during 1802-1824: A primary reference to understand the Dalton Minimum
Hisashi Hayakawa, Bruno P. Besser, Tomoya Iju +5
As we are heading towards the next solar cycle, presumably with a relatively small amplitude, it is of significant interest to reconstruct and describe the past grand minima on the…