Magneto-hydrodynamic interaction between planetary inner and outer cores

2015 Fiscal Year Final Research Report

• Project/Area Number: 25610139
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Meteorology/Physical oceanography/Hydrology
• Research Institution: Kyoto University
• Principal Investigator: Takehiro Shin-ichi 京都大学, 数理解析研究所, 准教授 (30274426)
• Co-Investigator(Kenkyū-buntansha): YAMADA MICHIO 京都大学, 数理解析研究所, 教授 (90166736)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 内核外核境界 / 相変化 / ジュール熱 / ダイナモ過程 / 核マントル境界 / 安定成層 / アルフベン波 / 貫入距離

Outline of Final Research Achievements

In order to elucidate fundamental characteristics of fluid motion in
planetary cores, magneto-hydrodynamic interaction between planetary inner and outer cores is investigated theoretically and numerically. First, inner core flows induced by Joule heating of the magnetic field penetrating from the outer core are obtained analytically and numerically. Second, penetration of fluid motions into the upper stably stratified layer near the top of the outer core is examined and the analytical expressions of penetration distance are derived. These expressions are validated by numerical calculations of magneto-hydrodynamic thermal convection in a rotating spherical shell. Finally, numerical experiments of the whole planetary central cores with a coupled inner-outer cores magneto-hydrodynamic fluid model are performed. It is shown that the inner core flows with upward and downward in the equatorial and polar regions respectively emerge.

Free Research Field

地球流体力学, 惑星内部物理学