Theoretical modeling of low‐latitude Mg+
Theoretical modeling of low‐latitude Mg+
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低纬度Mg+的理论模拟
DOI：
10.1029/ja088ia04p03211
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发表时间：
1983
影响因子：
--
通讯作者：
D. Anderson
中科院分区：
文献类型：
--
作者：
C. Fesen;P. Hays;D. Anderson
F区金属离子的形态是重要的，因为这些长寿命的离子作为示踪剂的动态过程。Mg+的行为是从赤道轨道大气探测器E卫星上的可见气辉实验观测到的2800 A共振发射推断出来的。数据是在接近冬至的5个月内，在太阳活动最大的条件下获得的。通过求解一个主要离子和一个次要离子的耦合连续性和动量方程，对Mg+密度进行了理论建模。假设在125 km的下边界处有一个由100个金属离子cm-3组成的均匀层。边界处密度的数值并不重要，因为所有结果都与边界密度成线性比例。计算再现了冬至条件下下午早些时候观察到的最大金属离子密度的外观，以及接近中午赤道附近几乎与高度无关的数密度分布。经度效应主要在黄昏附近的高海拔地区（约350公里）明显。高海拔密度与季节和太阳活动周期的相关性得到了支持：在太阳活动最大的条件下，在固定的高度上看到更大的密度，并在接近日落的春分点。中性风，特别是E区的中性风，对于确定高海拔金属离子分布非常重要。特别是E区潮汐振荡似乎是控制F区金属离子行为的最大单一因素。
F region metal ion morphology is important because these long-lived ions act as tracers of the dynamical processes. The behavior of Mg+ was inferred from the 2800 A resonance emission observed by the Visible Airglow Experiment on the Atmosphere Explorer E satellite in equatorial orbit. Data were obtained over 5 months near winter solstice during solar maximum conditions. Theoretical modelling of the Mg+ densities was undertaken by solving the coupled continuity and momentum equations for one major and one minor ion. A uniform layer of 100 metal ions cm−3 at the lower boundary of 125 km was assumed. The numerical value of the density at the boundary is not critical, as all results are linearly scaled to the boundary density. The calculations reproduced the observed appearance of largest metal ion densities in the early afternoon in winter solstice conditions, and number density profiles that are nearly altitude independent near the equator near noon. Longitudinal effects are apparent mainly at high altitudes (≳350 km) near dusk. Correlations of high altitude densities with season and solar cycle are supported: larger densities at fixed altitudes are seen during solar maximum conditions, and at equinox near sunset. Neutral winds, particularly in the E region, were found to be very important in determining the metal ion distribution at high altitudes. The E region tidal oscillations especially seem to be the largest single factor controlling the F region metal ion behavior.