Auroral Heating of Plasma Patches Due to High‐Latitude Reconnection
Auroral Heating of Plasma Patches Due to High‐Latitude Reconnection
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DOI：
10.1029/2021ja029657
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发表时间：
2021-11
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通讯作者：
Joaquín Díaz Peña;J. Semeter;Y. Nishimura;R. Varney;A. Reimer;M. Hairston;M. Zettergren;M. Hirsch;O. Verkhoglyadova;K. Hosokawa;K. Shiokawa
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作者：
Joaquín Díaz Peña;J. Semeter;Y. Nishimura;R. Varney;A. Reimer;M. Hairston;M. Zettergren;M. Hirsch;O. Verkhoglyadova;K. Hosokawa;K. Shiokawa
这项研究利用Resolute Bay非相干散射雷达（RISR-N）的体积采样能力，与全天空图像和现场测量合作，研究黎明侧高纬度叶重连事件期间冷等离子体传输和极光降水之间的相互作用。事件前的太阳风IMF的特点是在Bz > 0和By < 0的一段时间内嵌入Bz的脉冲负偏移。与高纬度重联脉冲相关的传输和磁应力释放的综合效应驱动了补丁和软电子沉淀之间的混合，创造了电子密度和温度升高的共同区域。在漂移斑块的静止框架中提取的垂直电离层剖面显示，在200公里以上Te和250公里以下Ne同时增加，而同时在F区域峰值附近仅显示Ne的小影响。这些观测结果表明了一种新的机制，可以产生一个“热点”，其中密度增强不是由降水产生的，而是由降水引起的。基于物理学的GEMINI模式被用来探索对观测到的降水的响应作为高度和时间的函数。模式结果表明，在DMSP高度（10800公里），即热斑，相关的增强Ne和Te，可以产生极光加热和向上扩散，而不考虑低海拔密度结构。该研究强调了在空间和时间上进行密集分布的观测的必要性，以了解受复杂强迫影响的地区的中尺度和小尺度电离层动力学。
This study exploits the volumetric sampling capabilities of the Resolute Bay Incoherent Scatter Radar (RISR‐N) in collaboration with all‐sky imagery and in situ measurements to examine the interplay between cold plasma transport and auroral precipitation during a high‐latitude lobe reconnection event on the dawn side. Solar wind IMF preceding the event was characterized by an impulsive negative excursion in Bz embedded within a period of Bz > 0 and By < 0. The combined effects of transport and magnetic stress release associated with a high‐latitude reconnection pulse drove a co‐mingling between patches and soft electron precipitation, creating common regions of elevated electron density and temperature. Vertical ionospheric profiles extracted in the rest frame of the drifting patch showed a contemporaneous increase in Te above 200 km and Ne below 250 km while at the same time showing only a small impact in Ne near the F‐region peak. The observations suggest a new mechanism for creating a “hot patch” wherein the density enhancement is not generated by the precipitation but is warmed by it. The physics‐based GEMINI model was used to explore the response to the observed precipitation as a function of altitude and time. Model results suggest that a correlated enhancement in Ne and Te at DMSP altitudes (∼800 km), that is, hot patch, can be produced by auroral heating and upward diffusion, irrespective of lower altitude density structure. The study highlights the need for densely distributed observations in space and time for understanding both mesoscale and small‐scale ionospheric dynamics in regions subject to complex forcing.