A study on ionospheric scintillation near the EIA crest in relation to equatorial electrodynamics
A study on ionospheric scintillation near the EIA crest in relation to equatorial electrodynamics
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EIA波峰附近电离层闪烁与赤道电动力学的研究
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
S. Banola
中科院分区：
文献类型：
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作者：
S. Chatterjee;S. Chakraborty;B. Veenadhari;S. Banola
赤道电射流（EEJ）数据被认为是赤道电场的代理指标，结合赤道电离探空仪、总电子含量（TEC）和太阳活动高年（2011-2012）春分月的赤道电离异常（EIA）波峰附近的闪烁数据进行分析，以识别赤道电子密度不规则性的日落后演化以及随后在赤道电离异常（EIA）波峰附近发生的闪烁数据。北部 EIA 波峰。仅考虑地磁安静和正常的电喷射日。闪烁日的 EEJ 日间轮廓表现出在日间峰值之后的下午到日落前的二次增强。 EEJ 二次增强后会出现一系列有利于产生不规则性的电动过程。 TEC 的纬度剖面显示出日落后时期 EIA 结构的复苏。 EIA 波峰附近的日间 TEC 剖面类似于 EEJ 下午增强的日子的日落后二次增强。赤道扩散 F 和 EIA 波峰附近的日落后闪烁的出现似乎是在 EEJ 中的二次增强事件之后发生的。研究发现，EEJ 增强的强度和持续时间对于 EIA 结构日落后的强化以及随后赤道不规则的发生都很重要。两者结合的临界值可以被认为是 EIA 波峰附近日落后出现闪烁的重要前兆。结果使用 1989-1990 年的存档数据进行了验证，并根据增强型赤道喷泉的调制效应进行了解释。
Equatorial electrojet (EEJ) data, which are considered as a proxy index of equatorial electric field, are analyzed in conjunction with equatorial ionosonde, total electron content (TEC) and scintillation data near the equatorial ionization anomaly (EIA) crest for the equinoctial months of high solar activity years (2011–2012) to identify any precursor index of postsunset evolution of equatorial electron density irregularities and subsequent occurrence of scintillation near the northern EIA crest. Only geomagnetically quiet and normal electrojet days are considered. The diurnal profiles of EEJ on the scintillation days exhibit a secondary enhancement in the afternoon to presunset hours following diurnal peaks. A series of electrodynamical processes conducive for generation of irregularities emerge following secondary enhancement of EEJ. Latitudinal profile of TEC exhibits resurgence in EIA structure around the postsunset period. Diurnal TEC profile near the EIA crest resembles postsunset secondary enhancement on the days with afternoon enhancement in EEJ. Occurrence of equatorial spread F and postsunset scintillation near the EIA crest seems to follow the secondary enhancement events in EEJ. Both the magnitude and duration of enhanced EEJ are found to be important for postsunset intensification of EIA structure and subsequent occurrence of equatorial irregularities. A critical value combining the two may be considered an important precursor for postsunset occurrence of scintillation near the EIA crest. The results are validated using archived data for the years 1989–1990 and explained in terms of modulation effects of enhanced equatorial fountain.