Radar imaging observations of the field-aligned irregularities at low-latitude ionosphere

我们分析了印度尼西亚一台工作频率为30.8 MHz的VHF背向散射雷达观测到的E区和F区场向不规则性(FAI)，揭示了FAI发生率的统计上的当地时间、季节和太阳活动的变化。研究了FAI的传播特性和漂移速度。特别是，我们研究了午夜后的F区FAI，并认为午夜后的FAI可能与等离子体气泡或中等尺度的行进电离层扰动(MSTID)有关。

We have analyzed E- and F-region field-aligned irregularities (FAIs) observed by a VHF backscatter radar with an operating frequency of 30.8 MHz in Indonesia and revealed statistically local time, seasonal, and solar activity variations of the FAI occurrence rates. Propagation characteristics and drift velocities of the FAIs are also investigated. Especially, we have studied the post-midnight F-region FAIs and suggested that the post-midnight FAIs are likely associated with either plasma bubbles or medium-scale traveling ionospheric disturbances (MSTIDs).