2015 Fiscal Year Final Research Report
New mechanism for geomagnetic polarity reversals induced by flow reversals
Project/Area Number |
24244073
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Research Category |
Grant-in-Aid for Scientific Research (A)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Solid earth and planetary physics
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Research Institution | Japan Agency for Marine-Earth Science and Technology |
Principal Investigator |
YANAGISAWA Takatoshi 国立研究開発法人海洋研究開発機構, 地球深部ダイナミクス研究分野, 主任研究員 (20359186)
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Co-Investigator(Kenkyū-buntansha) |
TASAKA Yuji 北海道大学, 工学研究院, 准教授 (00419946)
KAGEYAMA Akira 神戸大学, システム情報学研究科, 教授 (20260052)
SAKURABA Ataru 東京大学, 理学系研究科, 助教 (50345261)
MIYAGOSHI Takehiro 国立研究開発法人海洋研究開発機構, 地球深部ダイナミクス研究分野, 主任研究員 (60435807)
SUMITA Ikuro 金沢大学, 自然システム学系, 准教授 (90334747)
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Co-Investigator(Renkei-kenkyūsha) |
HAMANO Yozo 国立研究開発法人海洋研究開発機構, 地球深部ダイナミクス研究分野, 特任上席研究員 (90011709)
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Project Period (FY) |
2012-04-01 – 2016-03-31
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Keywords | 地磁気の逆転 / 液体金属の対流 / 流れ場の反転 / 室内実験 / 数値シミュレーション |
Outline of Final Research Achievements |
We explored magnetoconvection and rotating convection by means of laboratory experiments and numerical simulations, to elucidate the mechanism that induces geomagnetic polarity reversals. We established a regime diagram of convection in a liquid metal under the influence of imposed horizontal magnetic field. The searched space is summarized by the relation between buoyancy and magnetic force, in which a regime exists that reversals of flow direction repeat intermittently. We found that the key mechanism for flow reversals is an occurrence of large-scale circulation in a horizontal plane. We also performed numerical simulations of dynamos in a rotating spherical shell, and clarified the relation between polarity reversals and transitions of convection flow.
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Free Research Field |
固体地球惑星科学
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