AI 中文总结
该研究通过汉勒地区观测，揭示中纬度等离子体团块产生机制，发现其与MSTID相互作用使前沿衰减分叉。利用多手段证实其传播等特征，提出极化电场驱动等离子体传输产生团块的机制，并用多卫星数据验证。
AI 中文摘要
我们报告了在印度拉达克地区汉勒（北纬32.7°，东经78.9°；磁纬约24.1°N）于2021年7月6日地磁平静（Ap = 6）夜晚拍摄的O(1D) 630.0 nm全天空气辉图像中两种不同的夜间F区不规则现象：等离子体团块（局部密度增强）和中尺度行进电离层扰动（MSTID）的观测结果。全球垂直总电子含量（VTEC）地图显示，等离子体团块在出现在气辉图像之前在成像仪视场的南边缘之外发展，并主要向西传播，这在气辉和VTEC数据集中都得到了证实。多个GNSS接收器记录的时间VTEC波动进一步证实了成像仪视场之外等离子体团块和MSTID的存在。此外，FORMOSAT - 7/COSMIC - 2信噪比和ICON/MIGHTI风廓线表明在等离子体团块和MSTID附近的E区存在散逸层（ES）。我们提出，与MSTID或ES层相关的极化电场沿磁力线映射到低纬度，通过F层的垂直抬升驱动等离子体从F峰区域向上传输。这一F层抬升通过FORMOSAT - 7/COSMIC - 2在低地球轨道高度同时测量的原位O⁺/H⁺密度增强/降低得到证实。向上传输的等离子体在较高高度经历了减少的化学损失，产生局部VTEC增强（等离子体团块）。等离子体随后沿磁力线扩散到更高/更低纬度/高度（约250公里），进入成像仪视场，在那里O₂⁺增强的解离复合产生高强度气辉区域。有趣的是，等离子体团块与MSTID的等离子体耗尽前沿之间的相互作用由于来自高密度团块区域的等离子体流入导致前沿逐渐衰减和分叉。
英文摘要
We report observations of two distinct nighttime F-region irregularities, plasma blob (localized density enhancement) and medium-scale traveling ionospheric disturbance (MSTID), in O(1D) 630.0 nm all-sky airglow images from Hanle (32.7°N, 78.9°E; Mlat~24.1°N), Ladakh, India, during the geomagnetically quiet (Ap=6) night of 06 July 2021. Global vertical total electron content (VTEC) maps revealed that the plasma blob developed beyond the southern edge of imager's field-of-view before appearing in airglow images and propagated predominantly westward, as confirmed from both the airglow and VTEC datasets. The existence of the plasma blob and MSTID outside the imager field-of-view was further confirmed by temporal VTEC fluctuations recorded by multiple GNSS receivers. Additionally, FORMOSAT-7/COSMIC-2 signal-to-noise ratio and ICON/MIGHTI wind profiles indicated the presence of sporadic-E (ES) layers at E-region near both the plasma blob and the MSTID. We propose that polarization electric field associated with either MSTID or ES-layers mapped along magnetic field lines to lower latitudes, driving upward plasma transport from F-peak region through vertical uplift of the F-layer. This F-layer uplift was confirmed by simultaneous in-situ O+/H+ density enhancements/reductions at LEO altitudes measured by FORMOSAT-7/COSMIC-2. Upward-transported plasma experienced reduced chemical loss at higher altitudes, producing localized VTEC enhancements (plasma blob). The plasma subsequently diffused along magnetic field lines to higher/lower latitudes/altitudes (~250 km), entering imager's field-of-view, where enhanced dissociative recombination of O2+ produced high intensity airglow region. Interestingly, interaction between the plasma blob and MSTID's plasma-depleted front caused gradual decay and bifurcation of the front due to plasma influx from the high-density blob region.
