Equatorial F region vertical plasma drifts: Seasonal and longitudinal asymmetries in the American sector
Equatorial F region vertical plasma drifts: Seasonal and longitudinal asymmetries in the American sector
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DOI：
10.1029/ja091ia11p12055
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发表时间：
1986-03
影响因子：
--
通讯作者：
I. Batista;M. Abdu;J. Bittencourt
中科院分区：
文献类型：
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作者：
I. Batista;M. Abdu;J. Bittencourt
在太阳极大期条件下，根据对美国磁赤道沿线两个纵向分离台站的电离层F区等离子体垂直漂移（V/sub z/）增强的分析结果，研究了电离层F区等离子体垂直漂移（V/sub z/）增强的纵向和季节性不对称性。这两个站点分别是秘鲁的万卡约和巴西的福塔莱萨，它们的磁偏角明显不同。利用E区和F区电动力耦合过程的详细数值模拟解释了观测到的不对称性，同时考虑了有限磁偏角引起的磁赤道的不对称性。模拟结果与观测结果一致，表明某站点夜间F区垂直漂移前反峰的出现时间及其季节变化受该站点磁偏角的控制，该站点的磁偏角决定了其磁共轭E层日落时间的季节变化（从而决定了其综合Pedersen电导率纵向梯度）。而前向峰的振幅则受到磁偏角和热层纬向风分量的影响。
Longitudinal and seasonal asymmetries in the evening ionospheric F region plasma vertical drift (V/sub z/) enhancements, between two longitudinally separated stations situated along the magnetic equator, in the American sector, are investigated under solar maximum conditions, based on results obtained from the analysis of ionosonde data for these stations. The two stations are Huancayo, Peru, and Fortaleza, Brazil, which have markedly different magnetic declination angles. The observed asymmetries are interpreted using a detailed numerical simulation of the E and F region electrodynamic coupling process that takes into account also its asymmetry about the magnetic equator arising from the finite magnetic declination angle. The results of the simulation show, in agreement with observations, that the occurrence time of the evening F region vertical drift prereversal peak and its seasonal variation at a station are controlled by the magnetic declination angle at that station, which determines the seasonal variation of the sunset times (and hence the integrated Pedersen conductivity longitudinal gradient) at its magnetic conjugate E layers. The amplitude of the prereversal peak, on the other hand, undergoes the influence of the magnetic declination angle as well as of the thermospheric zonal wind component.