MHD convection and dynamo in a spherical thin shell

Akira Kageyama; Takuya Furuzono

Presentation information

[JJ] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS15] [JJ] Geophysical fluid dynamics-Transfield approach to geoscience

Wed. May 24, 2017 10:45 AM - 12:15 PM 106 (International Conference Hall 1F)

convener:Keita Iga(Atmosphere and Ocean Research Institute, The University of Tokyo), Shigeo Yoshida(Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University), Takatoshi Yanagisawa(Department of Deep Earth Structure and Dynamics Research, Japan Agency for Marine-Earth Science and Technology), Hidenori AIKI(Nagoya University), Chairperson:Keita Iga(Atmosphere and Ocean Research Institute, The University of Tokyo)

10:45 AM - 11:00 AM

[MIS15-01] MHD convection and dynamo in a spherical thin shell

*Akira Kageyama¹, Takuya Furuzono¹ (1.Graduate School of System Informatics, Kobe University)

Keywords:MHD dynamo, Spherical shell, Yin-Yang-Zhong grid

By means of computer simulation, we have studied thermal convection of a magnetohydrodynamic (MHD) fluid in a thin spherical shell, between two concentric spheres of radii r=0.9 and 1.0. The inner sphere of 0 <= r <= 0.9 is an electrical conductor in a solid state. MHD equations are solved in the outer convection layer and the magnetic diffusion equation is solved in the inner solid core. We have found, in slowly rotating states, that convection motion is organized as (i) a set of multiple ring rolls, or (ii) a single spiral roll, starting from a point and ending at its antipodal point. The diameter of the roll is the width of the shell (0.1). The rolls are dynamo: magnetic fields are generated by fluid flow in them. The simulations were performed on a full-spherical grid system, called Yin-Yang-Zhong grid.