极向运动极光结构和喉区极光光学观测特征的对比分析

利用中国北极黄河站高时间分辨率的三波段全天空成像仪极光观测数据，联合太阳风和行星际磁场等观测，分析了极向运动极光结构（PMAFs）和喉区极光的形成及演化特征.研究发现:一系列PMAFs与喉区极光事件同时出现在观测视野中，其中PMAFs主要发生在日侧极隙区极光卵赤道向边界的极向一侧，沿东西方向分布，点亮后向高纬运动；喉区极光紧靠PMAF一侧发生，从极光卵赤道向边界向低纬延伸，沿南北方向分布，点亮后向高纬偏西方向运动；观测期间PMAFs发生频率高于喉区极光；当PMAFs与喉区极光同时出现时，PMAFs可以与喉区极光几乎同时出现或略晚于喉区极光出现，持续时间较喉区极光短.观测结果表明:与PMAF相对应的磁层顶重联过程和与喉区极光对应的磁层顶凹陷导致的磁重联过程在日侧磁层顶上的相邻区域分别发生，两种极光事件的形成过程相对独立，可能不存在相互触发关系. 

Comparative Analysis of Optical Observation Characteristics between PMAFs and Throat Aurora

Both Poleward Moving Auroral Forms (PMAFs) and throat aurora are typical transient auroral structures occurred near the magnetic noon. Previous studies have shown that throat auroras contain PMAFs. However, their characteristics and the correlation between these two auroras are not clear yet. By using the observation data of the high-resolution All-Sky Imagers (ASI) at the Yellow River Station in Arctic, together with solar wind and Interplanetary Magnetic Field (IMF) observations, the evolution characteristics of polar ionospheric PMAFs and the throat aurora are detailedly analyzed. It was found that a series of PMAFs and throat auroras appeared in the field of view of the all-sky imagers of the Yellow River Station. Among them, PMAFs mainly occurred in polar side of the equatorial boundary of aurora oval dayside of cusp area, were distributed along the east-west direction, and extended to the high latitude after brightening. Throat auroras were distributed along the north-south direction, which extended to low latitude from equatorward of discrete auroral oval and moved to the west after brightening, usually exist in the side of PMAFs. The frequency of PMAFs during observed period is higher than that of the throat aurora. When PMAFs and the throat aurora appear simultaneously, PMAFs can appear almost simultaneously with throat aurora or slightly later than throat aurora, and have a shorter duration than throat aurora. Based on the above observations, we suggest that magnetopause reconnection corresponding to PMAFs and magnetopause reconnection mapping to throat aurora caused by magnetopause indentations are two relatively independent processes happening in adjacent magnetopause region. The formation processes of the two auroral events are relatively independent, and there may be no mutual triggering relationship.