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标题：On the coupling of fast and shear Alfvén wave modes by the ionospheric Hall conductance
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作者：C. L. Waters ; R. L. Lysak ; M. D. Sciffer 等
期刊名称：Earth, Planets and Space
电子版ISSN：1880-5981
出版年度：2013
卷号：65
期号：5
页码：385-396
DOI：10.5047/eps.2012.08.002
出版社：Springer Verlag
摘要：There are two low frequency, magnetised, cold plasma wave modes that propagate through the Earth’s magnetosphere.These are the compressional (fast) and the shear Alfvén modes.The fast mode distributes energy throughout the magnetosphere with the ability to propagate across the magnetic field.Previous studies of coupling between these two modes have often focussed on conditions necessary for mode coupling to occur in the magnetosphere.However, Kato and Tamao (1956) predicted mode coupling would occur for non-zero Hall currents.Recently, the importance of the Hall conductance in the ionosphere for low frequency wave propagation has been studied using one dimensional (1-D) models.In this paper we describe effects of the ionosphere Hall conductance on field line resonance and higher frequency, 0.1–5 Hz waves associated with the Ionospheric Alfvén Resonator (IAR).The Hall conductance reduces the damping time of field line resonances and Joule dissipation into the ionosphere.The Hall conductance also couples shear Alfvén waves trapped in the IAR to fast mode waves that propagate across the ambient magnetic field in an ionospheric waveguide.This coupling leads to the production of low frequency magnetic fields on the ground that can be observed by magnetometers. Key words ULF waves Hall current ionosphere.
关键词：ULF waves ;Hall current ;ionosphere