Linear theory and modeling of the Rayleigh-Taylor instability leading to the occurrence of equatorial spread F
Linear theory and modeling of the Rayleigh-Taylor instability leading to the occurrence of equatorial spread F
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DOI：
10.1029/96ja00682
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发表时间：
1996-12-01
影响因子：
2.8
通讯作者：
Sultan, PJ
中科院分区：
文献类型：
--
作者：
Sultan, PJ
在对赤道扩展F（ESF）的瑞利-泰勒（R-T）不稳定性机制的检验中，根据Haerendel（预印本，1973）的形式，考虑到物理参数沿沿着地磁通量管的变化，导出了线性不稳定性增长率γ（RT）。由此产生的伽马（RT）的形式扩展了以前的工作的结果，包括直接依赖于transequatorial中性风，纬向电场，垂直和水平电离层密度梯度，存在的E区，和化学重组。现实的大气层和电离层密度模型的输入是第一次使用，以定量计算的R-T增长率的一系列地球物理条件。本研究的主要结果是，时间/高度域具有积极的计算不稳定增长率被发现与观察到的时间/高度模式ESF发生在一个月和一年的时间框架。能够模拟ESF的气候发生的成功支持了用于不稳定机制的物理模型，并开辟了研究ESF可预测性的新途径。
In a test of the generally accepted Rayleigh-Taylor (R-T) instability mechanism for equatorial spread F (ESF) a linear instability growth rate gamma(RT) is derived following the formalism of Haerendel (preprint, 1973) which takes into account the variations of physical parameters along geomagnetic flux tubes. The resulting form of gamma(RT) extends the results of previous work by including direct dependencies on transequatorial neutral winds, zonal electric fields, vertical and horizontal ionospheric density gradients, the presence of an E region, and chemical recombination. Realistic atmospheric and ionospheric density model inputs are used for the first time to make quantitative calculations of R-T growth rates for a range of geophysical conditions. The key result of this study is that time/altitude domains having positive calculated instability growth rates are found to coincide with observed time/altitude patterns of ESF occurrence over both a monthly and a yearly time frame. This success in being able to model the climatological occurrence of ESF lends support to the physical model adopted for the instability mechanism and opens up new avenues of research into ESF predictability on a night-to-night and even an hour-to-hour basis.