著者

Ishii Mamoru Sugiura Masahisa Iyemori Toshihiko Slavin James A.

出版者

国立極地研究所

雑誌

Proceedings of the NIPR Symposium on Upper Atmosphere Physics (ISSN:09145613)

巻号頁・発行日

vol.6, pp.90-102, 1993-02

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There is generally high correlation between the orthogonal magnetic and electric field perturbations on the ionospheric field-aligned current region based on observations by polar orbiting satellites. The ratio between the magnetic and electric field perturbations, &lrtri;B_z/μ_oE_x, has a scale-length dependence : the ratio &lrtri;B_z/μ_oE_x decreases with decreasing scale length. B. FORGET et al.(J. Geophys. Res., 96,1843,1991) explained this scale-length dependence using a static model. In this paper, we compare the ratio &lrtri;B_z/μ_oE_x observed by the DE-2 satellite for various spatial scales with the effective Pedersen conductivity Σ_<p, eff> calculated by the method of FORGET et al. The results show that in many cases this model can adequately explain the observed scale-length dependence. However, cases exist in which the difference, &lrtri;B_z/μ_oE_x-Σ_<p, eff>, decreases at about 0.25-1.0s in temporal scales (2-8km in spatial scales). This behavior is explained as being due to Alfven waves.