赤道低纬电离层瑞利-泰勒不稳定性初始扰动波数的临界值

在文献1]推导的基础上将不稳定判据扩展到±30°磁纬之间的低纬地区.为研究初始扰动波数对等离子体泡的影响，分析了λ_min随初始扰动波数的变化规律，选择二分法计算λ_min=1时的临界波数α_c，并分析α_c随经纬度、太阳活动、季节、地方时以及水平东向电场强度的变化.主要结论如下:α_c随经纬度、季节、太阳活动以及地方时的变化规律和等离子体泡及闪烁活动的规律基本一致，α_c越小，等离子体泡越容易产生；水平东向电场增强有利于等离子体泡形成.α_c的值对人工影响电离层时选择最优扰动条件具有一定的指导意义. 

Critical Value of Initial Disturbance Wave-number Affecting Rayleigh-Taylor Instability in Equatorial and Low-latitude Ionosphere

The sufficient condition of Rayleigh-Taylor instability in equatorial ionosphere has been derived by Ref.1]. In this paper, the sufficient condition is expanded to low-latitude areas of ±30° magnetic latitude. To study how the initial disturbance wave-number affects the generation of plasma bubble, the variations of λ_min as initial disturbance wave-number are analysed. According to the dichotomy method, the critical wave-number α_c is attained for λ_min=1. Moreover, the characteristics of α_c with geomagnetic latitudes, longitudes, seasons, solar activities, local times and the horizontal eastern electric filed are analyzed. The main conclusions are as follows. The variations of α_c with latitudes, longitudes, seasons, solar activities, and local times are consistent with plasma bubbles and scintillations. The shorter the wave-length is, the easier it would be to generate the Plasma Bubbles (PB). The enhancements of the horizontal eastward electric filed are helpful to initiate PBs. The value of α_c is benificial to decide the best disturbed way in the ionospheric artificial modification.