Updated on 2022/03/23

写真a

 
MIYAKE Fusa
 
Organization
Institute for Space-Earth Environmental Research Division for Cosmic Ray Research Associate professor
Graduate School
Graduate School of Science
Title
Associate professor
Contact information
メールアドレス
External link

Degree 1

  1. 博士(理学) ( 2013.12   名古屋大学 ) 

Research Interests 2

  1. 宇宙線生成核種

  2. 太陽活動

Research Areas 1

  1. Natural Science / Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics

Current Research Project and SDGs 1

  1. 宇宙線生成核種を用いた過去の極端太陽現象の調査

Research History 3

  1. Nagoya University   Institute for Space-Earth Environmental Research Division for Cosmic Ray Research   Associate professor

    2017.4

  2. アリゾナ大学滞在研究員

    2015.1 - 2016.3

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    Country:United States

  3. Institute for Advanced Research (Institute for Space-Earth Environmental Research), Nagoya University   Designated assistant professor

    2014.4 - 2017.3

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    Country:Japan

Education 2

  1. Nagoya University   Graduate School, Division of Natural Science

    - 2013.12

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    Country: Japan

  2. Nagoya University   Faculty of Science

    - 2009.3

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    Country: Japan

Professional Memberships 4

  1. 日本物理学会

  2. 日本地球惑星科学連合

  3. 日本第四紀学会

  4. 応用物理学会

Awards 3

  1. 平成29年度 文部科学大臣表彰 若手科学者賞

    2017.4   文部科学省  

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    Country:Japan

  2. 育志賞

    2014   日本学術振興会  

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    Country:Japan

  3. 名古屋大学学術奨励賞

    2013   名古屋大学  

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    Country:Japan

 

Papers 40

  1. Another rapid event in the carbon-14 content of tree rings Reviewed

    F. Miyake, K. Masuda, T. Nakamura

    Nature Communications     2013

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/ncomms2873

  2. A signature of cosmic-ray increase in AD 774-775 from tree rings in Japan Reviewed

    F. Miyake, K. Nagaya, K. Masuda, T. Nakamura

    Nature     page: 240-242   2012

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    Authorship:Lead author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

  3. High-Resolution Be-10 and Cl-36 Data From the Antarctic Dome Fuji Ice Core (similar to 100 Years Around 5480 BCE): An Unusual Grand Solar Minimum Occurrence?

    Kanzawa K., Miyake F., Horiuchi K., Sasa K., Takano K., Matsumura M., Takahashi T., Motizuki Y., Takahashi K., Nakai Y., Ohtani K., Tada Y., Ochiai Y., Motoyama H., Matsuzaki H., Yamazaki A., Muramatsu Y., Yamagata T.

    JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS   Vol. 126 ( 10 )   2021.10

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Journal of Geophysical Research: Space Physics  

    Cosmogenic nuclides in tree rings and polar ice cores record the information of past cosmic ray intensities and solar activities. A large 14C increase over 10 years has been discovered around 5480 BCE. The 14C variations in this event differ from those of other short-term cosmic ray events and typical grand solar minima. To elucidate the cause of the 14C increase around 5480 BCE, we measured the 10Be and 36Cl concentrations in the Antarctic Dome Fuji ice core at quasi-annual and 4–5 years resolutions, respectively. Based on the combined 14C, 10Be, and 36Cl data, the 5480 BCE event was probably not caused by a solar proton event (SPE) or a gamma-ray event, because the 36Cl concentration did not significantly increase as expected in these events. The incremented 10Be data were enhanced similarly to those of recent grand solar minima, but more rapidly increased (over ∼10 years). These results suggest that an unusual grand solar minimum occurred around 5480 BCE, characterized by a rapidly decreasing solar activity.

    DOI: 10.1029/2021JA029378

    Web of Science

    Scopus

  4. A Single-Year Cosmic Ray Event at 5410 BCE Registered in C-14 of Tree Rings International coauthorship

    Miyake F., Panyushkina I. P., Jull A. J. T., Adolphi F., Brehm N., Helama S., Kanzawa K., Moriya T., Muscheler R., Nicolussi K., Oinonen M., Salzer M., Takeyama M., Tokanai F., Wacker L.

    GEOPHYSICAL RESEARCH LETTERS   Vol. 48 ( 11 )   2021.6

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Geophysical Research Letters  

    The annual 14C data in tree rings is an outstanding proxy for uncovering extreme solar energetic particle (SEP) events in the past. Signatures of extreme SEP events have been reported in 774/775 CE, 992/993 CE, and ∼660 BCE. Here, we report another rapid increase of 14C concentration in tree rings from California, Switzerland, and Finland around 5410 BCE. These 14C data series show a significant increase of ∼6‰ in 5411–5410 BCE. The signature of 14C variation is very similar to the confirmed three SEP events and points to an extreme short-term flux of cosmic ray radiation into the atmosphere. The rapid 14C increase in 5411/5410 BCE rings occurred during a period of high solar activity and 60 years after a grand 14C excursion during 5481–5471 BCE. The similarity of our 14C data to previous events suggests that the origin of the 5410 BCE event is an extreme SEP event.

    DOI: 10.1029/2021GL093419

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  5. Findings from an in-Depth Annual Tree-Ring Radiocarbon Intercomparison International coauthorship International journal

    L. Wacker, E. M. Scott, A. Bayliss, D. Brown, E. Bard, S. Bollhalder, M. Friedrich, M. Capano, A. Cherkinsky, D. Chivall, B. J. Culleton, M. W. Dee, R. Friedrich, G. W.L. Hodgins, A. Hogg, D. J. Kennett, T. D.J. Knowles, M. Kuitems, T. E. Lange, F. Miyake, M. J. Nadeau, T. Nakamura, J. P. Naysmith, J. Olsen, T. Omori, F. Petchey, B. Philippsen, C. Bronk Ramsey, G. V.Ravi Prasad, M. Seiler, J. Southon, R. Staff, T. Tuna

    Radiocarbon   Vol. 62 ( 4 ) page: 873 - 882   2020.8

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    © 2020 Cambridge University Press. All rights reserved. The radiocarbon (C) calibration curve so far contains annually resolved data only for a short period of time. With accelerator mass spectrometry (AMS) matching the precision of decay counting, it is now possible to efficiently produce large datasets of annual resolution for calibration purposes using small amounts of wood. The radiocarbon intercomparison on single-year tree-ring samples presented here is the first to investigate specifically possible offsets between AMS laboratories at high precision. The results show that AMS laboratories are capable of measuring samples of Holocene age with an accuracy and precision that is comparable or even goes beyond what is possible with decay counting, even though they require a thousand times less wood. It also shows that not all AMS laboratories always produce results that are consistent with their stated uncertainties. The long-term benefits of studies of this kind are more accurate radiocarbon measurements with, in the future, better quantified uncertainties.

    DOI: 10.1017/RDC.2020.49

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  6. THE INTCAL20 NORTHERN HEMISPHERE RADIOCARBON AGE CALIBRATION CURVE (0-55 CAL KBP) International coauthorship International journal

    Paula J. Reimer, William E. N. Austin, Edouard Bard, Alex Bayliss, Paul G. Blackwell, Christopher Bronk Ramsey, Martin Butzin, Hai Cheng, R. Lawrence Edwards, Michael Friedrich, Pieter M. Grootes, Thomas P. Guilderson, Irka Hajdas, Timothy J. Heaton, Alan G. Hogg, Konrad A. Hughen, Bernd Kromer, Sturt W. Manning, Raimund Muscheler, Jonathan G. Palmer, Charlotte Pearson, Johannes van der Plicht, Ron W. Reimer, David A. Richards, E. Marian Scott, John R. Southon, Christian S. M. Turney, Lukas Wacker, Florian Adolphi, Ulf Buentgen, Manuela Capano, Simon M. Fahrni, Alexandra Fogtmann-Schulz, Ronny Friedrich, Peter Koehler, Sabrina Kudsk, Fusa Miyake, Jesper Olsen, Frederick Reinig, Minoru Sakamoto, Adam Sookdeo, Sahra Talamo

    RADIOCARBON   Vol. 62 ( 4 ) page: 725 - 757   2020.8

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:UNIV ARIZONA DEPT GEOSCIENCES  

    Radiocarbon (C-14) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric C-14 concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international C-14 calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable C-14 offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the C-14 ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine C-14 data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.

    DOI: 10.1017/RDC.2020.41

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  7. 775 and 994 14C events in the tree-rings of northern Japanese trees International journal

    M. Hakozaki, F. Miyake, T. Nakamura

    Proceedings of EA-AMS 8 & JAMS-22     page: 89 - 90   2020.6

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    Language:English   Publishing type:Research paper (international conference proceedings)  

  8. Prolonged production of 14C during the ~660 BCE solar proton event from Japanese tree rings. Reviewed International journal

    Hirohisa Sakurai, Fuyuki Tokanai, Fusa Miyake, Kazuho Horiuchi, Kimiaki Masuda, Hiroko Miyahara, Motonari Ohyama, Minoru Sakamoto, Takumi Mitsutani, Toru Moriya

    Scientific reports   Vol. 10 ( 1 ) page: 660 - 660   2020.1

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    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 originate from extreme solar proton events (SPEs). Another rapid 14C increase, also known as the ca. 660 BCE event in German oak tree rings as well as increases of 10Be and 36Cl in ice cores, was presumed similar to the 775 CE event; however, as the 14C increase of approximately 10‰ in 660 BCE had taken a rather longer rise time of 3-4 years as compared to that of the 775 CE event, the occurrence could not be simply associated to an extreme SPE. In this study, to elucidate the rapid increase in 14C concentrations in tree rings around 660 BCE, we have precisely measured the 14C concentrations of earlywoods and latewoods inside the annual rings of Japanese cedar for the period 669-633 BCE. Based on the feature of 14C production rate calculated from the fine measured profile of the 14C concentrations, we found that the 14C rapid increase occurred within 665-663.5 BCE, and that duration of 14C production describing the event is distributed from one month to 41 months. The possibility of occurrence of consecutive SPEs over up to three years is offered.

    DOI: 10.1038/s41598-019-57273-2

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  9. Characterization of the Measured Events International journal

    Cliver E, Ebihara Y, Hayakawa H, Jull T, Mekhaldi F, Miyake F, Muscheler R

    EXTREME SOLAR PARTICLE STORMS: THE HOSTILE SUN     2020

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/2514-3433/ab404ach6

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  10. Measurements of Radionuclides International journal

    Wacker L, Baroni M, Mekhaldi F, Miyake F, Oinonen M

    EXTREME SOLAR PARTICLE STORMS: THE HOSTILE SUN     2020

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/2514-3433/ab404ach5

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  11. Further Search for Extreme Events International journal

    Miyake F, Ebihara Y, Hayakawa H, Maehara H, Mitsuma Y, Usoskin I, Wang F, Willis D. M

    EXTREME SOLAR PARTICLE STORMS: THE HOSTILE SUN     2020

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/2514-3433/ab404ach7

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  12. Extreme Solar Particle Storms The hostile Sun Introduction International journal

    Usoskin I, Miyake F

    EXTREME SOLAR PARTICLE STORMS: THE HOSTILE SUN     2020

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/2514-3433/ab404ach1

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  13. 古木から読み解く過去の宇宙

    三宅 芙沙

    日本歴史   Vol. 870号(11月号)   page: 74 - 75   2020

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    Language:English   Publishing type:Research paper (scientific journal)  

    CiNii Research

  14. Radiocarbon Production Events and their Potential Relationship with the Schwabe Cycle Reviewed International journal

    A. Scifo, M. Kuitems, A. Neocleous, B. J. S. Pope, D. Miles, E. Jansma, P. Doeve, A. M. Smith, F. Miyake, M. W. Dee

    Scientific Reports   Vol. 9 ( 1 ) page: 17056   2019.11

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/s41598-019-53296-x

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  15. The Earliest Candidates of Auroral Observations in Assyrian Astrological Reports: Insights on Solar Activity around 660 BCE Reviewed International journal

    H. Hayakawa, Y. Mitsuma, Y. Ebihara, F. Miyake

    Astrophys. J. Lett.   Vol. 884 ( 1 )   2019.10

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.3847/2041-8213/ab42e4

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  16. Cosmogenic Evidence for Past SEP Events International journal

    MIYAKE Fusa

    Proc. 36th International Cosmic Ray Conference     2019.8

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    Language:English   Publishing type:Research paper (international conference proceedings)  

  17. 過去3000年間の宇宙線強度年変動 International journal

    三宅芙沙, 増田公明, 中村俊夫, 箱﨑真隆, 木村勝彦, 門叶冬樹, 森谷透, 武山美麗, Jull T, Panyushkina I

    第20回AMSシンポジウム報告集     page: 83 - 86   2019.2

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    Language:Japanese   Publishing type:Research paper (other academic)  

  18. 10Be signature of the cosmic ray event in the 10th century CE in both hemispheres, as confirmed by quasi‐annual 10Be data from the Antarctic Dome Fuji ice core Reviewed International journal

    F. Miyake, K. Horiuchi, Y. Motizuki, Y. Nakai, K. Takahashi, K. Masuda, H. Motoyama, H. Matsuzaki

    Geophysical Research Letters   Vol. 46 ( 1 ) page: 11 - 18   2019.1

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:American Geophysical Union ({AGU})  

    DOI: 10.1029/2018GL080475

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  19. The measurement of ion-induced cloud nucleation irradiated with a 180-MeV nitrogen ion and proton beams at HIMAC accelerator facility International journal

    Suzuki A., Itow Y., Sako T., Nakayama T., Masuda K., Miyake F., Matsumi Y., Miura K., Kusano K.

    Proceedings of Science   Vol. 358   2019

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Proceedings of Science  

    Ion-induced nucleation by cosmic rays influenced by solar modulation is of interest, and several studies with radioactive sources or accelerator beams have been performed. We focused on ionization with high-linear energy transfer (LET) particles, such as protons, neutrons, and ions, in secondary cosmic rays and the ion density of the secondary cosmic rays near the ground using the excel-based program for calculating atmospheric cosmic-ray spectrum (EXPACS). According to the calculation, not only muons but also protons and neutrons leave substantial traces of solar modulation at an altitude of 3 km from the ground. To verify the ion-induced nucleation by these secondary high-LET cosmic rays, a chamber experiment was conducted at the accelerator facility HIMAC. Using a chamber with a capacity of 75 L, experiments were conducted by irradiating protons and nitrogen ion beams with a constant energy of 180 MeV/u with varying intensity. The experimental results confirm that the ion density and aerosol density increased as the beam intensity increased. The aerosol density was found to be proportional to the ion density, but irrelevant to the ionization density. It was concluded that the ion-induced nucleation by high-LET secondary cosmic rays, such as protons and neutrons, provides no evidence of enhancement owing to ionization density and cannot account for the claimed variation of cloud formation due to the solar modulation.

    Scopus

  20. Cosmogenic evidence for past SEP events International journal

    Miyake F.

    Proceedings of Science   Vol. 358   2019

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Proceedings of Science  

    Terrestrial cosmogenic nuclides (e.g., 14C, 10Be, and 36Cl) are primarily produced by galactic cosmic rays. However, a certain amount of these nuclides is also produced by solar energetic particles (SEPs) derived from sporadic solar events such as solar flares and coronal mass ejections. Cosmic ray increase events in AD 774/775, AD 993/994 (or AD 992/993), and ~BC 660 have been discovered using 14C data in tree rings (Miyake et al. 2012, 2013; Park et al. 2017). It is considered that the most plausible cause of these events was an extreme SEP events with very hard energy spectra based on 14C analyses of tree rings and 10Be and 36Cl analyses of ice cores (e.g., Mekhaldi et al. 2015; Miyake et al. 2015, 2019; Büntgen et al. 2018; O'Hare et al. 2019). These SEP events are estimated to be several dozens of times larger than the largest events seen in direct observations, and an event of that size might have a serious impact on modern society. Therefore, it is important to investigate the occurrence rate of past extreme events. In recent years, surveys of past SEP events have been actively conducted via cosmogenic nuclide measurements with high time resolution (~one-year resolution). Here the detected past SEP candidates and a further survey of similar events are reviewed.

    Scopus

  21. Author Correction: Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CE. Reviewed International journal

    Büntgen U, Wacker L, Galván JD, Arnold S, Arseneault D, Baillie M, Beer J, Bernabei M, Bleicher N, Boswijk G, Bräuning A, Carrer M, Ljungqvist FC, Cherubini P, Christl M, Christie DA, Clark PW, Cook ER, D'Arrigo R, Davi N, Eggertsson Ó, Esper J, Fowler AM, Gedalof Z, Gennaretti F, Grießinger J, Grissino-Mayer H, Grudd H, Gunnarson BE, Hantemirov R, Herzig F, Hessl A, Heussner KU, Jull AJT, Kukarskih V, Kirdyanov A, Kolář T, Krusic PJ, Kyncl T, Lara A, LeQuesne C, Linderholm HW, Loader NJ, Luckman B, Miyake F, Myglan VS, Nicolussi K, Oppenheimer C, Palmer J, Panyushkina I, Pederson N, Rybníček M, Schweingruber FH, Seim A, Sigl M, Churakova Sidorova O, Speer JH, Synal HA, Tegel W, Treydte K, Villalba R, Wiles G, Wilson R, Winship LJ, Wunder J, Yang B, Young GHF

    Nature communications   Vol. 9 ( 1 ) page: 5399   2018.12

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/s41467-018-07636-6

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  22. Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CE Reviewed International journal

    Buntgen Ulf, Wacker Lukas, Galvan J. Diego, Arnold Stephanie, Arseneault Dominique, Baillie Michael, Beer Jurg, Bernabei Mauro, Bleicher Niels, Boswijk Gretel, Brauning Achim, Carrer Marco, Ljungqvist Fredrik Charpentier, Cherubini Paolo, Christl Marcus, Christie Duncan A, Clark Peter W, Cook Edward R, D'Arrigo Rosanne, Davi Nicole, Eggertsson Olafur, Esper Jan, Fowler Anthony M, Gedalof Ze'ev, Gennaretti Fabio, Griessinger Jussi, Grissino-Mayer Henri, Grudd Hakan, Gunnarson Bjorn E, Hantemirov Rashit, Herzig Franz, Hessl Amy, Heussner Karl-Uwe, Jull A. J. Timothy, Kukarskih Vladimir, Kirdyanov Alexander, Kolar Tomas, Krusic Paul J, Kyncl Tomas, Lara Antonio, LeQuesne Carlos, Linderholm Hans W, Loader Neil J, Luckman Brian, Miyake Fusa, Myglan Vladimir S, Nicolussi Kurt, Oppenheimer Clive, Palmer Jonathan, Panyushkina Irina, Pederson Neil, Rybnicek Michal, Schweingruber Fritz H, Seim Andrea, Sigl Michael, Churakova (Sidorova, Olga, Speer James H, Synal Hans-Arno, Tegel Willy, Treydte Kerstin, Villalba Ricardo, Wiles Greg, Wilson Rob, Winship Lawrence J, Wunder Jan, Yang Bao, Young Giles H. F

    NATURE COMMUNICATIONS   Vol. 9 ( 1 ) page: 3605   2018.9

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/s41467-018-06036-0

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  23. 14Cスパイク法によるB-Tmテフラの精密年代と相関係数マッチング法の検討 International journal

    奥野充, 八塚槙也, 木村勝彦, 坂本稔, 箱﨑真隆, 洪完, 三宅芙沙, 増田公明, 中村俊夫

    国際火山噴火史情報研究集会講演要旨集2018-1     page: 50 - 54   2018.7

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    Language:Japanese   Publishing type:Research paper (conference, symposium, etc.)  

  24. 日本産樹木年輪の14Cオフセット International journal

    中村俊夫, 増田公明, 三宅芙沙, 箱﨑真隆, 奥野充

    国際火山噴火史情報研究集会講演要旨集2018-1     page: 31 - 41   2018.7

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  25. MORE RAPID C-14 EXCURSIONS IN THE TREE-RING RECORD: A RECORD OF DIFFERENT KIND OF SOLAR ACTIVITY AT ABOUT 800 BC? International journal

    Jull A. J. Timothy, Panyushkina Irina, Miyake Fusa, Masuda Kimiaki, Nakamura Toshio, Mitsutani Takumi, Lange Todd E, Cruz Richard J, Baisan Chris, Janovics Robert, Varga Tamas, Molnar Mihaly

    RADIOCARBON   Vol. 60 ( 4 ) page: 1237 - 1248   2018.6

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1017/RDC.2018.53

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  26. Verification of the annual dating of the 10th century Baitoushan volcano eruption based on an 774-775 radiocarbon spike Reviewed International journal

    M. Hakozaki, F. Miyake, T. Nakamura, K. Kimura, K. Masuda, M. Okuno

    Radiocarbon   Vol. 60 ( 1 ) page: 261 - 268   2018.2

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1017/RDC.2017.75

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  27. Study for elucidation of the 5480 BC cosmic ray event using cosmogenic nuclides 10Be and 36Cl.

    Takano Kenta, Sasa Kimikazu, Takahashi Tsutomu, Matsumura Masumi, Ochiai Yuta, Sueki Keisuke, Miyake Fusa, Horiuchi Kazuho, Matsuzaki Hiroyuki

    Abstracts of Annual Meeting of the Geochemical Society of Japan   Vol. 65 ( 0 ) page: 230   2018

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:GEOCHEMICAL SOCIETY OF JAPAN  

    <p>Recently, the increase of cosmic ray flux was found around 5480 BC using the <sup>14</sup>C measurements for tree rings with 1- to 2-y resolution. It is assumed that it may be caused by the large solar flares but we cannot specify the detail cause of this event. In this study, we aim to elucidate the cause of 5480 BC cosmic ray event by measuring <sup>10</sup>Be and <sup>36</sup>Cl in the ice core which was drilled at the Dome Fuji Station in Antarctica, and investigate the variation of cosmic ray flux around 5480 BC. The result of <sup>36</sup>Cl concentration variation using the Accelerator Mass Spectrometry (AMS) system in the University of Tsukuba is reported in this presentation. In addition, the performance of <sup>10</sup>Be-AMS and the future plan is also presented.</p>

    DOI: 10.14862/geochemproc.65.0_230

    CiNii Research

  28. 白頭山10世紀噴火のAD775 14C-spikeおよび酸素同位体比年輪年代測定に基づく年代検証 International journal

    箱﨑真隆, 三宅芙沙, 中村俊夫, 木村勝彦, 佐野雅規, 對馬あかね, 李貞, 中塚武, 増田公明, 奥野充

    Korea-Japan dendrochronology workshop toward a new phase of archeology     page: 22 - 22   2017.8

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  29. 樹木年輪と単年宇宙線イベント Invited International journal

    三宅芙沙, 増田公明, 中村俊夫, 箱崎真隆, 木村勝彦, I P Panyushkina・A J, T Ju

    第19回AMSシンポジウム・2016年度「樹木年輪」研究会共同開催シンポジウム報告集     page: 12 - 15   2017.6

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  30. SUPERNOVAE AND SINGLE-YEAR ANOMALIES IN THE ATMOSPHERIC RADIOCARBON RECORD Reviewed International journal

    Michael Dee, Benjamin Pope, Daniel Miles, Sturt Manning, Fusa Miyake

    RADIOCARBON   Vol. 59 ( 2 ) page: 293 - 302   2017.4

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:UNIV ARIZONA DEPT GEOSCIENCES  

    Single-year spikes in radiocarbon production are caused by intense bursts of radiation from space. Supernovae emit both high-energy particle and electromagnetic radiation, but it is the latter that is most likely to strike the atmosphere all at once and cause a surge in C-14 production. In the 1990s, it was claimed that the supernova in 1006 CE produced exactly this effect. With the C-14 spikes in the years 775 and 994 CE now attributed to extreme solar events, attention has returned to the question of whether historical supernovae are indeed detectable using annual C-14 measurements. Here, we combine new and existing measurements over six documented and putative supernovae, and conclude that no such astrophysical event has yet left a distinct imprint on the past atmospheric C-14 record.

    DOI: 10.1017/RDC.2016.50

    Web of Science

    Scopus

  31. SEARCH FOR ANNUAL C-14 EXCURSIONS IN THE PAST Reviewed International journal

    Fusa Miyake, Kimiaki Masuda, Toshio Nakamura, Katsuhiko Kimura, Masataka Hakozaki, A. J. Timothy Jull, Todd E. Lange, Richard Cruz, Irina P. Panyushkina, Chris Baisan, Matthew W. Salzer

    RADIOCARBON   Vol. 59 ( 2 ) page: 315 - 320   2017.4

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:UNIV ARIZONA DEPT GEOSCIENCES  

    Two radiocarbon excursions (AD 774-775 and AD 993-994) occurred due to an increase of incoming cosmic rays on a short timescale. The most plausible cause of these events is considered to be extreme solar proton events (SPE). It is possible that there are other annual C-14 excursions in the past that have yet to be confirmed. In order to detect more of these events, we measured the C-14 contents in bristlecone pine tree-ring samples during the periods when the rate of C-14 increase in the IntCal data is large. We analyzed four periods every other year (2479-2455 BC, 4055-4031 BC, 4465-4441 BC, and 4689-4681 BC), and found no anomalous C-14 excursions during these periods. This study confirms that it is important to do continuous measurements to find annual cosmic-ray events at other locations in the tree-ring record.

    DOI: 10.1017/RDC.2016.54

    Web of Science

    Scopus

  32. Atmospheric impacts of the strongest known solar particle storm of 775 AD Reviewed International journal

    Timofei Sukhodolov, Ilya Usoskin, Eugene Rozanov, Eleanna Asvestari, William T. Ball, Mark A. J. Curran, Hubertus Fischer, Gennady Kovaltsov, Fusa Miyake, Thomas Peter, Christopher Plummer, Werner Schmutz, Mirko Severi, Rita Traversi

    SCIENTIFIC REPORTS   Vol. 7   page: 45257   2017.3

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:NATURE PUBLISHING GROUP  

    Sporadic solar energetic particle (SEP) events affect the Earth's atmosphere and environment, in particular leading to depletion of the protective ozone layer in the Earth's atmosphere, and pose potential technological and even life hazards. The greatest SEP storm known for the last 11 millennia (the Holocene) occurred in 774-775 AD, serving as a likely worst-case scenario being 40-50 times stronger than any directly observed one. Here we present a systematic analysis of the impact such an extreme event can have on the Earth's atmosphere. Using state-of-the-art cosmic ray cascade and chemistry-climate models, we successfully reproduce the observed variability of cosmogenic isotope Be-10, around 775 AD, in four ice cores from Greenland and Antarctica, thereby validating the models in the assessment of this event. We add to prior conclusions that any nitrate deposition signal from SEP events remains too weak to be detected in ice cores by showing that, even for such an extreme solar storm and sub-annual data resolution, the nitrate deposition signal is indistinguishable from the seasonal cycle. We show that such a severe event is able to perturb the polar stratosphere for at least one year, leading to regional changes in the surface temperature during northern hemisphere winters.

    DOI: 10.1038/srep45257

    Web of Science

    Scopus

    PubMed

  33. Large C-14 excursion in 5480 BC indicates an abnormal sun in the mid-Holocene Reviewed International journal

    Fusa Miyake, A. J. Timothy Jull, Irina P. Panyushkina, Lukas Wacker, Matthew Salzer, Christopher H. Baisan, Todd Lange, Richard Cruz, Kimiaki Masuda, Toshio Nakamura

    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   Vol. 114 ( 5 ) page: 881 - 884   2017.1

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:NATL ACAD SCIENCES  

    Radiocarbon content in tree rings can be an excellent proxy of the past incoming cosmic ray intensities to Earth. Although such past cosmic ray variations have been studied by measurements of C-14 contents in tree rings with &gt;= 10-y time resolution for the Holocene, there are few annual C-14 data. There is a little understanding about annual C-14 variations in the past, with the exception of a few periods including the AD 774-775 C-14 excursion where annual measurements have been performed. Here, we report the result of C-14 measurements using the bristlecone pine tree rings for the period from 5490 BC to 5411 BC with 1- to 2-y resolution, and a finding of an extraordinarily large C-14 increase (20 parts per thousand) from 5481 BC to 5471 BC (the 5480 BC event). The C-14 increase rate of this event is much larger than that of the normal grand solar minima. We propose the possible causes of this event are an unknown phase of grand solar minimum, or a combination of successive solar proton events and a normal grand solar minimum.

    DOI: 10.1073/pnas.1613144114

    Web of Science

    Scopus

    PubMed

  34. High-precision age determination of Holocene samples by radiocarbon dating with accelerator mass spectrometry at Nagoya University

    T. Nakamura, K. Masuda, F. Miyake, M. Hakozaki, K. Kimura, H. Nishimoto, E. Hitoki

    Quaternary International     2015

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.quaint.2015.04.014

  35. Cosmic ray event of A.D. 774-775 shown in quasi-annual 10Be data from the Antarctic Dome Fuji ice core

    F. Miyake, A. Suzuki, K. Masuda, K. Horiuchi, H. Motoyama, H. Matsuzaki, Y. Motizuki, K. Takahashi, Y. Nakai

    Geophys. Res. Lett.     2015

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1002/2014GL062218

  36. 屋久杉に刻まれた宇宙現象

    三宅芙沙,増田公明

    物理学会誌   Vol. 69 ( 2 ) page: 93-97   2014

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

  37. Verification of the cosmic ray event in AD 993-994 by using a Japanese Hinoki tree

    F. Miyake, K. Masuda, M. Hakozaki, T. Nakamura, F. Tokanai, K. Kato, K. Kimura, and T. Mitsutani

    Radiocarbon     2014

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.2458/56.17769

  38. Radiocarbon ages of annual rings from Japanese wood: Evident age offset based on IntCal09

    T. Nakamura, K. Masuda, F. Miyake, K. Nagaya, T. Yoshimitsu

    Radiocarbon     page: 763-770   2013

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    Language:English   Publishing type:Research paper (scientific journal)  

  39. Lengths of Schwabe cycles in the 7th and 8th centuries indicated by precise measurement of carbon-14 content in tree rings

    F. Miyake, K. Masuda, T. Nakamura

    J. Geophys. Res.     2013

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1002/2012JA018320

  40. Variation of the Schwabe Cycle Length During the Grand Solar Minimum in the 4th Century BC Deduced from Radiocarbon Content in Tree Rings

    K. Nagaya, K. Kitazawa, F. Miyake, K. Masuda, Y. Muraki, T. Nakamura, H. Miyahara, H. Matsuzaki

    Solar Physics     page: 232-236   2012

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    Language:English   Publishing type:Research paper (scientific journal)  

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Books 1

  1. Extreme Solar Particle Storms: The hostile Sun

    F. Miyake, I. Usoskin, S. Poluianov( Role: Sole author)

    Institute of Physics Publishing  2019.12 

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    Language:Japanese

MISC 3

  1. 低緯度における大気中宇宙線生成核種Be‐7濃度の季節変動と地球規模での大気流跡線解析 International journal

    鈴木颯一郎, 櫻井敬久, 門叶冬樹, 乾恵美子, 三宅芙沙, 増田公明, MITTHUMSIRI Warit, RUFFOLO David, MACATANGAY R

    日本物理学会講演概要集(CD-ROM)   Vol. 74 ( 1 ) page: ROMBUNNO.14aK407‐10   2019.3

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    Language:Japanese  

    J-GLOBAL

  2. 屋久杉年輪の<sup>14</sup>C濃度測定による12‐14世紀の太陽活動の調査 International journal

    三宅芙沙, 森千尋, 増田公明, 中村俊夫, 木村勝彦, 門叶冬樹

    名古屋大学年代測定研究   Vol. 2   page: 113‐114   2018.3

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    Language:Japanese  

    J-GLOBAL

  3. 平成28年度名古屋大学総長裁量経費 地域貢献事業「樹木年輪・年縞堆積物から過去の太陽活動,地球の古気候を探る」活動報告 International journal

    南 雅代, 北川淳子, 小島秀彰, 榎並正樹, 加藤丈典, 三宅芙沙, 池田晃子, 窪田 薫, 栗田直幸, 吉田澪代, 椋本ひかり, 藤沢純平, 徳丸 誠, 中村俊夫, 北川浩之

    名古屋大学年代測定研究報告   Vol. 1   page: 170-182   2017.3

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    Language:Japanese   Publishing type:Internal/External technical report, pre-print, etc.  

Presentations 6

  1. 樹木年輪の炭素14濃度に刻まれた過去の宇宙線増加現象 Invited

    三宅 芙沙

    第79回応用物理学会 秋季学術講演会  2018.9 

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    Language:Japanese   Presentation type:Oral presentation (invited, special)  

  2. 樹木年輪から探る過去の大規模SPE Invited

    三宅 芙沙

    SGEPSS  2018.11 

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    Language:Japanese   Presentation type:Oral presentation (invited, special)  

  3. Rapid cosmic ray events shown in carbon-14 data of tree rings Invited International conference

    F. Miyake

    PSTEP A04 International Workshop  2019.2 

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    Language:English   Presentation type:Oral presentation (invited, special)  

  4. Cosmogenic Evidences for Past SEP Events Invited International conference

    F. Miyake

    36th International Cosmic Ray Conference, Madison  2019.7 

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    Language:English   Presentation type:Oral presentation (keynote)  

  5. Annual cosmic ray events shown in carbon-14 data from the BC 10th to AD 14th century International conference

    F. Miyake

    23rd Radiocarbon conference  2018.6 

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    Language:English   Presentation type:Oral presentation (keynote)  

  6. A search for past extreme solar events using 14C data in tree rings Invited International conference

    F. Miyake

    Chapmann conference (Chapman on Scientific Challenges Pertaining to Space Weather Forecasting Including Extremes)  2019.2 

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    Language:English   Presentation type:Oral presentation (invited, special)  

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Research Project for Joint Research, Competitive Funding, etc. 1

  1. 宇宙線生成核種による過去数万年の宇宙線大変動探索計画

    2014.9 - 2016

KAKENHI (Grants-in-Aid for Scientific Research) 11

  1. Solar activity over the past 10,000 years

    Grant number:20H05643  2020.8 - 2025.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (S)

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\198120000 ( Direct Cost: \152400000 、 Indirect Cost:\45720000 )

  2. 宇宙線生成核種を用いたシュワーベサイクル検出手法の確立

    Grant number:20K20918  2020.7 - 2023.3

    科学研究費助成事業  挑戦的研究(萌芽)

    三宅 芙沙, 堀内 一穂, 箱崎 真隆, 早川 尚志

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\6370000 ( Direct Cost: \4900000 、 Indirect Cost:\1470000 )

    年輪の14Cや氷床コアの10Beといった宇宙線生成核種は過去の長期的な太陽磁場活動の優れた代替データである。一方、太陽活動を議論する上で大変重要となる太陽11年周期(シュワーベサイクル)は、核種データに現れる振幅が小さいため、宇宙線生成核種を用いた検出手法が未だ確立していない。本研究では、月解像度の年輪14Cデータと、複数地点の氷床コア10Beデータを分析することで、シュワーベサイクル検出法の確立を目指す。本研究が実現することにより、黒点データの妥当性を検証することが可能となるだけでなく、過去数万年間のシュワーベサイクルの調査につながり、太陽物理学をはじめ革新的な影響を及ぼす。
    年輪の14Cや氷床コアの10Beなどの宇宙線生成核種は過去の長期的な太陽磁場活動の優れた代替データである。一方、太陽活動を議論する上で重要となる太陽11年周期(シュワーベサイクル)は、核種データに現れる振幅が小さいため、宇宙線生成核種を用いた検出手法が未だ確立していない。本研究では、1年未満の時間分解能の年輪14Cデータと、複数地点の氷床コア10Beデータを分析することで、シュワーベサイクル検出法の確立を目指す。本研究が実現することにより、黒点データの妥当性の検証や過去数万年間のシュワーベサイクルの調査を可能とする。
    2020年度は、1年未満の時間分解能で樹木年輪の14C濃度測定を実施するため、2つの年層内剥離方法を試みた。1つ目の手法は、ミクロトームを用いて年層内を等分に剥離し、その後通常の化学処理でセルロースを抽出する方法であり、他方は板状の木片からセルロースを抽出し(板毎セルロース抽出法)、その後顕微鏡下で1年輪を複数等分にする方法である。試料の形状や試料調整者の技術によって、分割可能な数は異なるが、今回実施した3等分程度であれば容易に分離可能であり、年輪幅が大きければさらに多く分割可能であることを確認した。2つの手法を用いて分離した試料の14C濃度測定を実施したが、どちらの手法でも得られる14C濃度に違いは見られず先行研究とも再現性のある結果が得られた。年輪の形状によって上記2つの手法でそれぞれ長所、短所があるため、今後は分析に用いる試料に適した手法を用いる予定である。
    また、10Be分析に用いる予定の南極氷床コアについて、年代の推定方法について検討を行った。
    2020年度は、本研究を進める上での基盤となる年輪年層内剥離方法を確立し、分析に必要なサンプルの準備を進めることができたため、おおむね計画通りに進展しているが、試料の選定にあたって追加調査する必要が生じたため、本来予定していた14C分析の実現までは至らなかった。
    2020年度の分析から、樹種によって樹木の炭素固定に違いが生じる可能性が判明したため、まずは同一年代(1950年以降)に同じ地域で生息していた樹木を用いて年層内14C変動に違いがみられないか確認し、リアルタイムの炭素をより固定している分析に適した試料を選定する。そして、2020年度に検討を行ったサンプルの分析手法を適用し、1825-1850年を超高精度な年輪14Cと氷床コア10Be分析を行う予定である。

  3. Dendrochronological study for precise chronology of the past 30,000 years of extreme climate and disaster history

    Grant number:20H00035  2020.4 - 2025.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

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    Authorship:Coinvestigator(s)  Grant type:Competitive

  4. 最新型AMS装置の高精度化による単年14Cスパイク年代決定法の研究

    Grant number:20H01369  2020.4 - 2024.3

    科学研究費助成事業  基盤研究(B)

    門叶 冬樹, 宮原 ひろ子, 尾嵜 大真, 白石 哲也, 三宅 芙沙

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    Authorship:Coinvestigator(s)  Grant type:Competitive

    近年、太陽活動や太陽圏環境の変動の他、天体現象にともなうと考えられる突発的な宇宙線増加現象が、14C濃度の異常上昇(14Cスパイク)として過去に度々発生していたことが明らかになりつつある。
    本研究は、最新型のコンパクト加速器質量分析(AMS)システムの高精度化の研究を行い、樹木1年輪毎に対する高精度14C年代AMS測定から、新しい14Cスパイク年代を見出すことで、地域や樹種の差別化なく分解能1年の精度で文化財年代を決定する新しい放射性炭素年代法を創出することである。
    近年、太陽活動や太陽圏環境の変動の他、天体現象にともなうと考えられる突発的な宇宙線増加現象が、14C濃度の異常上昇(14Cスパイク)として過去に度々発生していたことが明らかになりつつある。日本で発見された14Cスパイクを用いた新しい年代測定法を世界に先駆けて確立するために、樹木単年輪中の14C濃度を高精度に分析するための研究開発を開始した。本年度は、山形大学、東京大学、パレオ・ラボが有する、同タイプの最新型コンパクトAMSシステム(NEC社製 0.5MV-1.5SDH)を用いて、十分な統計精度と低い系統誤差による14C濃度分析を目標に、以下の開発研究を行った。
    まず、イオン源に設けたCs収束用レンズの電極構造と印加電圧の依存性をイオン光学設計ソフトSIMION 3Dを用いて最適化した。次に、試料が装填されたカソード位置(最大40個)に対する炭素ビーム(C-/C+)の透過効率依存性を調べ、各位置でのビーム制御に対する考察を行った。そして、各カソード位置および測定回数に応じたビーム制御を行うために、14C+ビームの焦点面に設置する新しい位置有感型放射線検出器を開発した。
    試料中の14C濃度を高精度に分析するための研究開発は、順調に進展している。今年度はAMSの焦点面に設置する予定の新しい位置有感型放射線検出器の開発を行った。開発した検出器は、64チャンネルの電極を持つ半導体検出器であり、1MeVのエネルギーを持つ14Cビームを高いエネルギー分解能で検出することを目的に、薄い不感層をシリコン半導体検出器を開発した。また、最新型コンパクトAMSシステムにおいて、未知試料数点の14C濃度測定行い、施設間のクロスチェックを行った。
    国産樹木単年輪中からの14Cスパイク検出の研究については、青森県下北半島から採取されたアスナロ試料の準備を行った。使用したアスナロは年輪年代が西暦1191年から1330年、1329年から1450年のサンプルであり、各サンプルから1年輪試料を剥離することを行った。
    14Cスパイク年代測定方法の文化財試料への応用研究については、唐古・鍵遺跡から出土した炭化物試料について、AMS測定の準備を開始した。
    コンパクトAMS用に開発した64チャンネルの電極を持つシリコン半導体検出器の基礎特性試験を行う。具体的には、241Am線源から放出されるα線を0度と45度の角度で入射させ、不感層の厚み、エネルギー分解能、それぞれの位置依存性を調べる。
    国産樹木単年輪中からの14Cスパイク検出の研究については、薄膜状化した1年輪試料について化学処理を施して試料から不純物を取り除く作業を行ったのち、塩素漂白、濃アルカリ処理によってα-セルロースを抽出する予定である。また、14Cスパイク年代測定方法の文化財試料への応用研究については、引き続き唐古・鍵遺跡から出土した木材についてAMSを用いた14C濃度測定を行う。

  5. 多核種分析による完新世の極端太陽現象の頻度と規模解明

    Grant number:20H00173  2020.4 - 2021.3

    科学研究費助成事業  基盤研究(A)

    三宅 芙沙, 堀内 一穂, 宮原 ひろ子, 笹 公和, 箱崎 真隆, 前原 裕之, 木村 勝彦, 門叶 冬樹, 早川 尚志

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\45110000 ( Direct Cost: \34700000 、 Indirect Cost:\10410000 )

    樹木年輪の14Cや氷床コアの10Be、36Clといった宇宙線生成核種は、観測史上最大とされ
    る1956年のSEP(Solar Energetic Particle)イベントの数十倍という過去の超巨大SEPイ
    ベントの優れた代替データである。本研究は、主に年輪の14C分析から、完新世(
    過去1万2千年間)における最大のSEPイベントの同定と、超巨大SEPイベントの発生頻度及
    びその発生特性の解明を目的とする。我々の太陽における発生特性を、太陽型恒星の恒星
    フレアと比較することで、太陽型恒星における太陽の普遍性と特殊性を評価する。
    樹木年輪の炭素14や氷床コアのベリリウム10、塩素36といった宇宙線生成核種は、直接観測で見つかっている最大のSEP(Solar Energetic Particle)イベントの数十倍という過去の超巨大SEPイベントの優れた代替データである。これまでに我々の宇宙線生成核種の分析から、775年や994年などの超巨大SEPイベントの痕跡を発見した(Miyake et al. 2012, 2013)。これは、我々の太陽でスーパーフレアが発生した可能性を示すだけでなく、現代社会に甚大な影響を与え得る極端太陽現象が将来発生する可能性を示すものである。本研究は、宇宙線生成核種の分析から、完新世(過去1万2千年間)における最大のSEPイベントの同定と、超巨大SEPイベントの発生頻度及びその発生特性の解明を目的とする。
    今年度は、長期的な樹木年輪の炭素14分析を実施するために、樹木試料の手配(日本、フィンランド、カリフォルニア産の樹木サンプル)や、試料調製装置(木片試料からグラファイト試料の抽出)の性能チェック、さらに分析に必要な環境作りを行った。また、SEPイベントのエネルギースペクトルを評価する上で要となる塩素36の(南極ドームふじ氷床コア)分析を行った。さらに、トラバーチン堆積物のベリリウム10データに過去の大規模SEPイベントがみられるか調査する足掛かりとして、トラバーチン分析を行うための環境整備を行った。
    令和2年度が最終年度であるため、記入しない。
    令和2年度が最終年度であるため、記入しない。

  6. 高解像度マルチアーカイブ分析による太陽地磁気変動史と宇宙線イベントの解明

    Grant number:19H00706  2019.4 - 2023.3

    科学研究費助成事業  基盤研究(A)

    堀内 一穂, 宮原 ひろ子, 三宅 芙沙, 川村 賢二, 山崎 俊嗣, 小田 啓邦, 笹 公和

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    Authorship:Coinvestigator(s)  Grant type:Competitive

    研究代表者らは、アイスコアや堆積物および年輪などのマルチアーカイブに含まれる宇宙線生成核種を対比に利用した「宇宙線層序」を開拓することで、限られた区間とは言え、宇宙線強度の高解像度でロバストな変動曲線を得ることに成功した。この手法で得られた曲線は、過去の太陽活動や地磁気強度変動、さらには様々な突発的宇宙線イベントを解明する手がかりとなる。本研究ではこの手法を発展させ、さらなる宇宙線生成核種記録の獲得と宇宙線層序による海陸の詳細対比を目指す。さらにこれに基づいて、地質時代の太陽活動・地磁気強度変動史を解明するとともに、未知の宇宙線イベントを見いだす。
    南極ドームふじアイスコアを利用して、酸素同位体ステージ6の百年解像度ベリリウム10分析を行った。また、同コアのガス分析融解水を用いた分析を行うことで、35万から50万年前にて地磁気極小期に関わるベリリウム10増加イベントを複数検出した。さらに、同コアの数値年代を主にガス分析に基づいて向上させた。これらに加えて、西太平洋赤道域の海底堆積物(WCBコア)を主な対象にした地磁気極小期の高時間解像度ベリリウム同位体分析を行った。堆積物から得られたデータは、古地磁気強度変動記録やドームふじアイスコアのベリリウム10記録と、逐次比較された。
    単年解像度での分析が必要な完新世の宇宙線イベントに関して、17世紀前半の特異な太陽活動周期を詳細に解明し、論文として公表した。また、完新世の複数のイベントを対象にして、ドームふじアイスコアにて単年解像度でのベリリリウム10分析や数年解像度での塩素36分析を行った。さらに、中国雲南省の陸域炭酸塩堆積物(トラバーチン)を対象に、単年解像度のベリリウム10分析を本格的に開始した。これについては、本年度は特に、歴史時代の太陽極小期に焦点を当てた分析を行った。
    東太平洋赤道域深海底堆積物(U1335コア)のベリリウム同位体比を過去数十万年間連続的に分析し、これを堆積物から得られた古地磁気強度変動記録と比較することで、双方に刻まれた変動の確かな類似性を見出した。以上の結果を得るための基礎的な研究の成果を公表するとともに、研究をまとめるために個別の打ち合わせを行った。
    本事業は大きく分けて、(1)過去50万年間の高解像度宇宙線生成核種記録の獲得と宇宙線層序による海陸の詳細対比、(2)宇宙線層序に挿入する数値年代の向上、(3)太陽活動・地磁気変動史の詳細解明、(4)未知宇宙線イベントの探索と発見、(5)宇宙線層序編年の高度化と拡張を目標としている。本年度は、新型コロナウイルスの影響で、アイスコア試料の分取や研究成果の公表に停滞を余儀なくされたが、他の事項は順調に進行した。
    計画の遂行に大きな問題は生じていないことから、当初の計画通り課題を推進する予定である。

  7. Radiocarbon measurement of annual tree-ring to clarify regional effect and fine structure on calibration curve

    Grant number:18H03594  2018.4 - 2022.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

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    Authorship:Coinvestigator(s)  Grant type:Competitive

  8. Occurrence rate of extreme SPEs for the last 5000 years

    Grant number:16H06005  2016.4 - 2020.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (A)

    Miyake Fusa

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\23920000 ( Direct Cost: \18400000 、 Indirect Cost:\5520000 )

    Large-scale Solar Proton Events (SPEs), originate from solar flares and coronal mass ejections, can cause enormous damage such as a breakdown of artificial satellites. Although the large-scale SPEs have been observed directly for the past ~70 years, the longer-term characteristics of SPE (e.g., their occurrence rate and upper limit) are not well understood. The purpose of this study is to investigate the signatures of large-scale SPEs occurred in the past by measuring the 14C concentration of tree rings, which is a proxy for large-scale SPE, with a one-year resolution and capturing a rapid increases in 14C concentrations. We aim to clarify the occurrence rate of large-scale SPEs and the relationship between the occurrence of large-scale SPEs and solar activity.

  9. Repetitive 14C measurements for understanding of occurrence distribution of extreme SPEs in the 7-10th centuries

    Grant number:16K13802  2016.4 - 2019.3

    Miyake Fusa

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    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\3640000 ( Direct Cost: \2800000 、 Indirect Cost:\840000 )

    Rapid 14C increase events have been discovered in 774-775 and 993-994 CE by continuous 14C concentration measurements of tree rings. The most plausible cause of these 14C increase events are an extreme Solar Proton Event (SPE). Such extreme SPEs cause the destruction of satellites and terrestrial communication networks, and can be a natural disaster in modern society comparable to huge eruptions and earthquakes. The purpose of this study is to detect more 14C increase events smaller than the 775 and 994 events by an ultra-high precision measurement of 14C concentrations in annual tree rings for the period 600-1000 CE, and clarify an occurrence rate of 14C events. Although we detected some smaller 14C events, further validation will be necessary to identify the extreme SPE origins.

  10. 宇宙線生成核種を用いた過去2500年の巨大SPE調査

    2014.4 - 2016.3

    科学研究費補助金 

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    Authorship:Principal investigator 

  11. 樹木年輪中放射性炭素14濃度測定による過去の宇宙線強度の復元

    2012.4 - 2014.3

    科学研究費補助金 

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    Authorship:Principal investigator 

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Teaching Experience (On-campus) 7

  1. Paleo Cosmic Ray Physics

    2020

  2. 物理学実験I

    2020

  3. 物理学実験II

    2020

  4. Cosmic-ray Physics Seminar 4

    2020

  5. 地球学

    2020

  6. 太陽地球系科学

    2020

  7. 宇宙科学

    2020

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Social Contribution 27

  1. 中日文化センター 巨大太陽フレアと地球環境

    Role(s):Lecturer

    2018.3

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    Audience: Junior students, High school students, College students, Graduate students, Teachers, Guardians, General

    Type:Lecture

  2. 麗澤瑞浪 中学・高等学校 研究室紹介

    Role(s):Lecturer

    2017.11

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    Audience: Junior students, High school students

    Type:Other

  3. わかりやすい科学 「科学のたまご」を君のこころに 科学講座

    2017.2

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    Audience: Schoolchildren, Guardians

    Type:Lecture

  4. 小・中学生向け夏休み体験学習「樹木年輪・年縞堆積物から過去の太陽活動、地球の古気候を探る」

    Role(s):Lecturer

    2016.8

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    Audience: Schoolchildren, Junior students

    Type:Lecture

  5. 名古屋大学宇宙地球環境研究所公開講演会「嵐を測る」

    Role(s):Lecturer

    2016.7

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    Audience: General

    Type:Lecture

  6. 駿台天文講座

    2015.9

  7. サロン・ド・Arimoto

    2014.10

  8. 愛知県図書館サイエンスセミナー

    2014.8

  9. 名古屋市科学館公開セミナー

    2014.8

  10. 南山高等・中学校女子部 理科講演会

    2014.7

  11. 岡崎ロータリークラブ創立63周年記念例会

    2014.6

  12. 昭和高校文化講演会

    2014.3

  13. さかえサイエンストーク

    2012.10

  14. 屋久杉に刻まれた過去の太陽活動

    Role(s):Lecturer

    仁科記念講演会「アイソトープで探る宇宙」  2018.11

  15. 古木に記された過去の巨大太陽フレアー

    Role(s):Lecturer

    中日文化センター  巨大太陽フレア―と地球環境  2018.3

  16. 過去の太陽と樹木年輪

    Role(s):Lecturer

    名古屋大学  小・中学生向け夏休み体験学習「樹木年輪・年縞堆積物から過去の太陽活動、地球の古気候を探る」  2016.8

  17. 過去の太陽嵐を探る

    Role(s):Lecturer

    名古屋大学宇宙地球環境研究所公開講演会「嵐を測る」  2016.7

  18. 宇宙線の歴史を屋久杉で探る

    Role(s):Lecturer

    駿台天文講座  2015.9

  19. 樹木年輪から探る過去の宇宙線変動

    Role(s):Lecturer

    サロン・ド・Arimoto  2014.10

  20. 屋久杉に刻まれた謎の放射線バースト

    Role(s):Lecturer

    名古屋市科学館  公開セミナー  2014.8

  21. 屋久杉を用いた過去の宇宙線観測

    Role(s):Lecturer

    愛知県図書館  サイエンスセミナー  2014.8

  22. 屋久杉が語る過去の宇宙線急増イベント

    Role(s):Lecturer

    南山高等・中学校女子部  理科講演会  2014.7

  23. 屋久杉が語る過去の太陽活動

    Role(s):Lecturer

    名大祭太陽研講演会  2014.6

  24. 屋久杉に記録された奈良・平安時代の放射線バースト

    Role(s):Lecturer

    岡崎ロータリークラブ創立63周年記念例会  2014.6

  25. 屋久杉が語る過去の宇宙線急増イベント

    Role(s):Lecturer

    昭和高校  文化講演会  2014.3

  26. NHKBS

    Role(s):Media coverage

    コズミックフロント  2013

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    Audience: Media

    Type:TV or radio program

  27. 屋久杉が語る奈良時代の宇宙線強度~急激な増加の謎~

    Role(s):Lecturer

    さかえサイエンストーク  2012.10

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Media Coverage 1

  1. コズミック フロント☆NEXT

    2018.5