This study investigates the impact of vertical ionospheric drift during daytime on the evolution of predawn equatorial plasma bubbles by conducting model simulations using “Sami3 is Another Model of the Ionosphere.” The upward drift of the ionosphere transports bubbles to higher altitudes, where their lifetime is set by the atomic oxygen photoionization rate. While the bubbles generated at predawn persist into dayside, the bubbles generated shortly after sunset diminish before sunrise. Therefore, post-sunset bubbles do not contribute to daytime electron density irregularities. Bubbles maintain their field-aligned characteristics throughout the daytime regardless of the vertical ionospheric drift. This property allows bubbles to exist near the magnetic equator despite poleward plasma transport by the fountain process. The shift of irregularity concentration to higher latitudes over time in satellite observations is explained by the combined effect of transport of bubbles to higher altitudes and rapid refilling of depletions near the magnetic equator.

中文翻译：

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垂直等离子体运动对黎明前赤道等离子体气泡白天演化的影响

本研究通过使用“Sami3是电离层的另一个模型”进行模型模拟，研究了白天垂直电离层漂移对黎明前赤道等离子体气泡演化的影响。电离层的向上漂移将气泡传送到更高的高度，其寿命由原子氧光电离率决定。虽然黎明前产生的气泡持续到白天，但日落后不久产生的气泡在日出前就会消失。因此，日落后的气泡不会导致白天电子密度的不规则性。无论垂直电离层漂移如何，气泡在整个白天都保持其场对齐特性。尽管通过喷泉过程向极地进行等离子体传输，该特性仍允许气泡存在于磁赤道附近。卫星观测中不规则浓度随着时间的推移向更高纬度的转移可以通过气泡向更高海拔的传输和磁赤道附近损耗的快速重新填充的综合效应来解释。