低纬电离层对穿透电场的响应

Response of the low-latitude ionosphere to penetration electric field and related dynamical and electrodynamical processes are the hot topics of current ionospheric weather research. Utilizing satellite and ground based observations, this project is devoted to study the efficiency and time delay of solar wind electric field penetration into the equatorial ionosphere, to reveal the differencies of penetration efficiency during the events which are driven by interplanetary coronal mass ejections(ICME) and corotating interaction region (CIR), and to build the quantitative relationship between equatorial electrojet and electric field at different longitudes. Moreover, we plan to perform statistical studies on how the low-latitude ionospheric electron density varies under space weather events, to investigate their longitudinal, latitudinal, seasonal and local time dependencies, and to perform theoretical analysis of physical mechanisms in combination with the 2-D mid- and low-latitude ionospheric model TIME-IGGCAS, and to uncover the importance of electrodynamical processes in the disturbed ionosphere. This study will be conducive to understand the coupling processes between interplanetary solar wind, magnetosphere and ionosphere, and improve our current understanding in ionospheric weather, and guide the empirical modeling of the ionospheric storms.

穿透电场驱动的低纬电离层时空变化及相关的动力学、电动力学过程是电离层天气学的研究热点。本项目拟利用卫星和地基综合观测资料，以穿透电场为主要研究对象，采用事例研究与统计分析方法，研究在磁暴期间低纬电离层穿透电场响应太阳风电场的效率和时延，比较行星际日冕物质抛射和共转相互作用区期间穿透电场效率的异同点，建立不同经度扇区赤道电急流与电场的定量关系；在此基础上，进行电离层天气学尺度扰动特征的研究，揭示低纬电离层电子浓度对磁暴响应的经度、纬度、季节、地方时依赖性，并借助于实验室自主研发的理论模式，结合数值模拟的方法分析其中物理过程及机制,尤其是揭示穿透电场对低纬电离层显著性变化的重要性。项目实施有助于深化对太阳风-磁层-电离层耦合机制的理解，推进对低纬电离层天气学特征的认知，从而为低纬电离层暴时经验建模提供参考。

穿透电场驱动的低纬电离层时空变化及高纬和低纬电离层的耦合过程是电离层天气学的研究热点，也是尚不清楚的科学问题。本项目充分结合了卫星和地基综合观测资料，以及理论模式模拟结果，以穿透电场为主要研究对象，采用事例研究与统计分析方法，充分研究在磁暴期间低纬电离层响应太阳风电场的特征，比较了不同扇区响应的异同点。研究创新点有：短时间多重快速的穿透电场出现在稳定的IMF Bz南向期间，抬升了日落时赤道电离层，增强了EIA结构特征; 受到电场的作用美洲扇区出现附加分层结构；另外还研究了电场与中高纬暴时电子密度增强的关系，分析其物理过程及机制； 给出了暴时密度增强的世界时依赖性。项目实施深化了电离层响应太阳风机制的理解，加强了暴时低纬与中高纬电离层耦合的认识，为低纬电离层暴时经验建模提供参考。