Variations of topside ionospheric electron density near the dawn terminator in relation to geomagnetic activity
學年 106
學期 1
出版（發表）日期 2017-11-27
作品名稱 Variations of topside ionospheric electron density near the dawn terminator in relation to geomagnetic activity
作品名稱（其他語言）
著者 Sunny W.Y. Tam; Chien-Han Chen; Kaiti Wang
單位
出版者
著錄名稱、卷期、頁數 Journal of Space Weather and Space Climate, 7, A31, pp.1-20
摘要 A statistical study to determine the influence of geomagnetic disturbances on the ionosphere across the dawn terminator at subauroral and middle latitudes is performed, based on the vertical electron density profiles measured by the GPS Occultation Experiment aboard the FORMOSAT-3/COSMIC satellites from August 2006 to July 2009. Three ranges of solar zenith angles are adopted to characterize transitions between the pre- and post-dawn ionosphere. Results indicate opposing plasma density effects at the darkened and sunlit locations between 50° and 65° magnetic latitude (λm). The darkened topside ionosphere features density increases associated with geomagnetic activity, while density reductions mark its sunlit counterpart. The average electron peak density in the F2 region can increase by up to 44% in the darkened ionosphere and decrease by up to 20% in the sunlit ionosphere as Kp changes from 0–1 to 4–5. In the λm = 55°–65° range, the dominant contributors to the density perturbation are auroral electron precipitation for the darkened region and enhanced penetration electric fields for the sunlit region, with the transition occurring across the terminator local times. Dominance shifts first to electric fields at 50°–55°, then to aurora-induced neutral wind at 45°–50°, suggesting that during disturbed times electric fields seldom penetrate below λm = 50°. Findings presented in this statistical study should contribute to the study of space weather and the understanding of non-local influences of geomagnetic disturbances on topside dynamics.
關鍵字 solar zenith angle;penetration electric fields;auroral electron precipitation;neutral wind;dawnside ionosphere
語言 en
ISSN 2115-7251
期刊性質 國外
收錄於 SCI
產學合作
通訊作者
審稿制度 是
國別 FRA
公開徵稿
出版型式 ,電子版
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機構典藏連結 ( http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/112423 )

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