[M-IS28_1AM1] 日本における巨大地磁気誘導電流

[MIS28-06] 電離層電流の地電流電磁的結合：非一様・非等方性伝導度の効果

*吉川 顕正¹ (1.九州大学国際宇宙天気科学・教育センター)

キーワード：電離層電流, 地電流, 電磁結合系

lectromagnetically coupled system between upper atmosphere and inner earth, is discussed. It is well known that upper atmosphere and inner earth system is electromagnetically coupled across very small conducting atmospheric region, which means 'primary' induced electric field produced by the mutual coupling is almost inductive (divergence free). However if the conductivity distribution is inhomogeneous, 'secondary' polarization (curl-free) electric field can be produced at the region of conductivity gradient. In the ionosphere, non-uniform Hall conductivity distribution induces the Hall polarization field, which becomes cause of current concentration and potential deformation by the Cowling effect. Formation of Cowling channel is one of the most important and peculiar nature of weakly ionized system under strongly background magnetic field distribution.In this presentation, we will introduce basic feature of electrodynamics at the non-uniform and anisotropically conducting ionosphere, and will discuss a possible electromagnetic coupling mechanism when the telluric conductivity distribution is non-uniform and anisotropic.