Measurements of melting temperatures of ice and ammonia in the Mbar regime

• Project/Area Number: 16K05612
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Petrology/Mineralogy/Economic geology
• Research Institution: Ehime University (2017-2018); Tohoku University (2016)
• Principal Investigator: Kimura Tomoaki 愛媛大学, 地球深部ダイナミクス研究センター, 特別研究員 (50624540)
• Research Collaborator: Murakami Motohiko
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000); Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2016: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: アンモニア / 融解 / 超イオン / 天王星 / 海王星 / ブリュアン散乱分光計測 / 水 / ブリュュアン散乱 / 氷 / ブリュアン散乱分光法 / ラマン散乱分光法 / 高温高圧実験 / ブリルアン散乱 / ラマン散乱 / 惑星内部構造 / 物性実験 / 高圧物性 / 惑星内部磁場

Outline of Final Research Achievements

We have developed Brillouin-Raman scattering spectroscopy combined with CO2 laser heating system and measured sound velocity and Raman spectra of ammonia under high pressure and temperature conditions corresponding to the planetary interiors. The melting temperatures of ammonia have been determined up to 60 GPa based on the observation of the Brillouin peaks derived from the sound velocity of the liquid phase. We found the superionic phase at 2000 K more than 40 GPa, which is ionized solid with the anomalously low sound velocity. The low sound velocity of the superionic ammonia, which is comparable to that of the liquid, suggested that the superionic components does not contribute on the suppression of the mantle convection.

Academic Significance and Societal Importance of the Research Achievements

天王星と海王星の惑星磁場は多重極磁場であることが知られているがその磁場生成メカニズムは明らかになっていなかった。惑星深部の対流が抑制される内部構造が磁場生成に関与していることが提案されているが、そのような非対流層が形成される原因は未解明である。本研究でアンモニアの超イオン相の弾性波速度の実験計測に初めて成功した。計測した超イオン相の弾性波速度は液体と同等であることが明らかになり、惑星深部の非対流層を形成する要因として提案されていた超イオン物質は対流の抑制に寄与していないことがわかった。

Research Products

• [Int'l Joint Research] ETH Zurich(スイス)
• [Journal Article] Application of Laser Technology for Static and Dynamic Compression Experiments (2018)
  • Author(s): KIMURA Tomoaki
  • Journal Title: The Review of High Pressure Science and Technology Volume: 28 Issue: 2 Pages: 131-138
  • DOI: 10.4131/jshpreview.28.131
  • NAID: 130007402264
  • ISSN: 0917-639X, 1348-1940
  • Peer Reviewed / Open Access
• [Journal Article] Melting temperatures of MgO under high pressure by micro-texture analysis (2017)
  • Author(s): T. Kimura, H. Ohfuji, M. Nishi, T. Irifune
  • Journal Title: Nature Communications Volume: 8 Issue: 1 Pages: 15735-15735
  • DOI: 10.1038/ncomms15735
  • Peer Reviewed / Open Access
• [Journal Article] Shock Compression Response of Forsterite above 250 Gpa (2016)
  • Author(s): T. Sekine, N. Ozaki, Y.Asaumi, T. Kimura, K. Miyanishi, B. Albertazzi, Y. Sato,Y. Sakawa, T.Sano, S. Sugita, T. Matsui, and R. Kodama
  • Journal Title: Sci. Adv. Volume: 2(8) Issue: 8 Pages: 31600157-31600157
  • DOI: 10.1126/sciadv.1600157
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Dynamic compression of dense oxide (Gd3Ga5O12) from 0.4 to 2.6 TPa: Universal Hugoniot of fluid metals (2016)
  • Author(s): N. Ozaki, W. J. Nellis, T. Mashimo, M. Ramzan, R. Ahuja, T. Kaewmaraya, T. Kimura, M. Knudson, K. Miyanishi, Y. Sakawa, T. Sano, and R. Kodama
  • Journal Title: Sci. Rep. Volume: 6, Issue: 1 Pages: 26000-26000
  • DOI: 10.1038/srep26000
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] CO2レーザーと組み合わせたブリュアンーラマン散乱分光システム (2018)
  • Author(s): 木村友亮、村上元彦
  • Organizer: 第５９回高圧討論会
• [Presentation] 両側CO2レーザー加熱システムを用いたMgOの高圧融点決定 (2018)
  • Author(s): 木村友亮
  • Organizer: 光・量子ビーム科学合同シンポジウム
  • Invited
• [Presentation] Melting temperatures of MgO up to ~50 GPa determined by micro-texture analysis (2017)
  • Author(s): Tomoaki Kimura, Hiroaki Ohfuji, Masayuki Nishi, Tetsuo Irifune
  • Organizer: JpGU-AGU Joint Meeting 2017
  • Place of Presentation: 幕張メッセ
  • Year and Date: 2017-05-20
  • Int'l Joint Research
• [Presentation] Melting temperatures of MgO up to ~50 GPa determined by micro-texture analysis (2017)
  • Author(s): T. Kimura, H. Ohfuji, M. Nishi, T. Irifune
  • Organizer: JpGU-AGU Joint Meeting 2017
  • Int'l Joint Research
• [Presentation] Melting temperatures of MgO up to ~50 GPa by micro-texture analysis (2017)
  • Author(s): T. Kimura, H. Ohfuji, M. Nishi, T. Irifune
  • Organizer: International Joint Graduate Program Workshop in Earth and Environmental Science
  • Int'l Joint Research
• [Presentation] レーザー技術の静・動的圧縮実験への応用 (2017)
  • Author(s): 木村友亮
  • Organizer: 第58回高圧討論会
  • Invited
• [Presentation] 超イオンNH3で形成される天王星と海王星の安定成層 (2017)
  • Author(s): 木村友亮、村上元彦
  • Organizer: 第58回高圧討論会
• [Presentation] Melting temperatures of MgO under high pressure determined by micro-texture observantion (2016)
  • Author(s): Tomoaki Kimura, Hiroaki Ohfuji, Masayuki Nishi, Tetsuo Irifune
  • Organizer: AGU fall meeting 2016
  • Place of Presentation: San Francisco
  • Year and Date: 2016-12-12
  • Int'l Joint Research
• [Presentation] Melting curve of MgO under high pressure constrained by micro-texture observantion (2016)
  • Author(s): Tomoaki Kimura
  • Organizer: Gordon Research Seminar
  • Place of Presentation: Holderness School
  • Year and Date: 2016-07-16
  • Int'l Joint Research / Invited
• [Presentation] 高圧下のタンタル(Ta)の融解直前の構造と融点の決定 (2016)
  • Author(s): 木村友亮
  • Organizer: レーザー研シンポジウム
  • Place of Presentation: 大阪大学 吹田キャンパス
  • Year and Date: 2016-04-19
• [Remarks] Experimental Mineral Physics, ETH Zurich
  • URL: http://mineralphysics.ethz.ch/
• [Remarks] 愛媛大学 地球深部ダイナミクス研究センター
  • URL: http://grc.ehime-u.ac.jp/
• [Remarks] CO2レーザー加熱DACを用いたMgO融点精密決定に成功
  • URL: http://www.grc.ehime-u.ac.jp/archives/2258
• [Remarks] 地球のマントルはどのようにしてできたのか？
  • URL: https://academist-cf.com/journal/?p=5437
• [Remarks] 木村友亮さんと柿澤翔さんが高圧討論会で受賞
  • URL: http://www.grc.ehime-u.ac.jp/archives/2908