Multi-instrumental analysis of the day-to-day variability of equatorial plasma bubbles
Multi-instrumental analysis of the day-to-day variability of equatorial plasma bubbles
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DOI：
10.3389/fspas.2023.1167245
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发表时间：
2023-03
期刊：
影响因子：
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通讯作者：
Ercha Aa;Shunrong Zhang;A. Coster;P. Erickson;W. Rideout
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文献类型：
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作者：
Ercha Aa;Shunrong Zhang;A. Coster;P. Erickson;W. Rideout
本文介绍了在2019年12月7日至10日地磁安静时间段内，对美国扇区赤道等离子体气泡（EPBs）变化的多仪器观测分析。通过协调利用全球尺度的翼盘观测（GOLD）紫外图像、电离层连接探测器（ICON）的现场和遥感数据、全球导航卫星系统（GNSS）的总电子含量（TEC）观测以及电离层探空仪测量，研究了EPB的日常变化及其潜在的驱动因素。主要结果如下：（1）日落后EPB强度在同一UT间隔内有较大的日变化，在07年12月夜间较为明显，08和09年12月受到明显抑制，10日显著恢复和增强。2)日落后的线性瑞利-泰勒不稳定增长率表现出不同的变化模式。它在12月7日和8日有一个相对温和的峰值，但在12月9日和10日有一个较大的峰值。2009年12月9日晚的生长速率高峰与其他晚相比有2 h的时滞。该分析未显示峰值生长速率与观察到的EPBs强度之间的确切一对一关系。3)EPB的逐日变化与电离层扰动和大气重力波的特征有较好的一致性，在12月7日和10日观测到的EPB之前/伴随着相对较强的波动，而在12月8日和9日则相对较弱。这些坐标观测表明，与AGW相关的初始波浪式播种扰动，以及不稳定增长率的催化因素，共同对调节EPB的日常变化发挥了重要作用。一个强的播种扰动可以有效地补偿一个中等强度的瑞利-泰勒不稳定性增长率，因此，它们的组合效应可以促进EPB的发展。缺乏适当的播种扰动将使它成为一个更低效的过程中的EPBs的发展，特别是与延迟的瑞利-泰勒不稳定性增长率的峰值。
This paper presents a multi-instrument observational analysis of the equatorial plasma bubbles (EPBs) variation over the American sector during a geomagnetically quiet time period of 07–10 December 2019. The day-to-day variability of EPBs and their underlying drivers are investigated through coordinately utilizing the Global-scale Observations of Limb and Disk (GOLD) ultraviolet images, the Ionospheric Connection Explorer (ICON) in-situ and remote sensing data, the global navigation satellite system (GNSS) total electron content (TEC) observations, as well as ionosonde measurements. The main results are as follows: 1) The postsunset EPBs’ intensity exhibited a large day-to-day variation in the same UT intervals, which was fairly noticeable in the evening of December 07, yet considerably suppressed on December 08 and 09, and then dramatically revived and enhanced on December 10. 2) The postsunset linear Rayleigh-Taylor instability growth rate exhibited a different variation pattern. It had a relatively modest peak value on December 07 and 08, yet a larger peak value on December 09 and 10. There was a 2-h time lag of the growth rate peak time in the evening of December 09 from other nights. This analysis did not show an exact one-to-one relationship between the peak growth rate and the observed EPBs intensity. 3) The EPBs’ day-to-day variation has a better agreement with that of traveling ionospheric disturbances and atmospheric gravity waves signatures, which exhibited relatively strong wavelike perturbations preceding/accompanying the observed EPBs on December 07 and 10 yet relatively weak fluctuations on December 08 and 09. These coordinate observations indicate that the initial wavelike seeding perturbations associated with AGWs, together with the catalyzing factor of the instability growth rate, collectively played important roles to modulate the day-to-day variation of EPBs. A strong seeding perturbation could effectively compensate for a moderate strength of Rayleigh-Taylor instability growth rate and therefore their combined effect could facilitate EPB development. Lacking proper seeding perturbations would make it a more inefficient process for the development of EPBs, especially with a delayed peak value of Rayleigh-Taylor instability growth rate.