论文部分内容阅读
讨论了中低纬度电离层F区中有碰撞的Rayleigh-Taylor不稳定性的线性增长率,着重考察背景中性风对增长率的影响,首先建立了适合于描述中低纬地区R-T不稳定性的基本方程,其中包括背景中性风和电场。在此基础上导出了色散关系和不稳定性增长率γ。结果表明,γ随纬度增加而逐渐减小,虽然东西方向和垂直向下的中性风分量有利于不稳定性增长,但在比30度更高的纬度,正常的背景中性风很难使γ为正值,除非存在合适的东西方向电场,亦即电场在中纬度Spread F的形成方面起着重要的作用。文中还根据比较合乎实际的电离层电子密度分布模式估算了线性增长率γ的季节变化。
The linear growth rate of the collision Rayleigh-Taylor instability in the F zone at middle and low latitudes was discussed. The influence of the neutral wind on the growth rate was investigated emphatically. At first, a method suitable for describing the RT instability The basic equations, including background neutral wind and electric field. On this basis, the relationship between dispersion and instability growth rate γ is derived. The results show that γ decreases gradually with the increase of latitude. Although the neutral wind component of east-west direction and vertical downwind contributes to the instability growth, at normal latitudes higher than 30 degrees, normal background neutral wind is difficult to make γ is positive unless there is a suitable east-west electric field, that is, the electric field plays an important role in the formation of Spread F at mid-latitudes. The paper also estimates the seasonal variation of linear growth rate γ based on the more realistic ionospheric electron density distribution model.