Ground magnetic perturbations associated with the standing toroidal mode oscillations in the magnetosphere-ionosphere system

Hiroyuki Nakata, Shigeru Fujita, Akimasa Yoshikawa, Masahiro Itonaga, Kiyohumi Yumoto

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

The behavior of toroidal mode oscillations of standing Alfvén waves (refer to as standing Alfvén oscillations) in the coupled magnetosphere-ionosphere system is investigated using a trapezoid-shape magnetosphere model. It is found that the magnetic perturbation is transmitted across the ionosphere differently in the two cases where the ionospheric electric field perturbation is static (Pedersen conductivity > Hall conductivity) and where it is inductive (Pedersen conductivity < Hall conductivity). It is noted that the ionospheric Hall current for the inductive condition shields the magnetic field perturbation. The north-south asymmetry of the conjugate ground magnetic perturbations is calculated by using a trapezoid model with the ionospheric and magnetospheric parameters based on the IGRF and IRI. It is revealed that the ionospheric electric field is almost static for the fundamental mode oscillation, whereas inductive for the higher harmonic ones. It is also found that the north-south asymmetry of the ground magnetic perturbations depends not only on the L-value but also on magnetic longitude; this is because the ionosphere and magnetic field conditions are not uniform as a function of longitude.

Original languageEnglish
Pages (from-to)601-613
Number of pages13
Journalearth, planets and space
Volume52
Issue number9
DOIs
Publication statusPublished - 2000

All Science Journal Classification (ASJC) codes

  • Geology
  • Space and Planetary Science

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