摘要(英) |
Data from ROCSAT-1 and DMSP F-13 SSJ/4 satellite are used to study the phenomena of the anomalous increase of heavy ions (mainly NO+) in the topside ionosphere. We focus on the unusual events of NO+ anomaly observed during the magnetic storm on 20 November 2003 for detailed analyses. At 600 km altitude, ROCSAT-1 normally observed the percentage content of NO+ to be less than 1% in the mid-latitude ionosphere under geo-magnetically quiet conditions. However, ROCSAT-1 did observe high percentage (> 5%) of NO+ spanned large portions of at least three satellite paths during the November 2003 storm. We analyze ROCSAT-1 IPEI data including ion density, velocity and temperature as well as the SSJ/4 particle data from DMSP for these NO+ events. We found that these events occurred in the magnetic local time sector of 04:00~10:00 LT and in the magnetic latitude range of 40 to 50 degrees, which were close to the precipitating ion equatorward boundaries. In addition, these events were found in the temperature enhanced regions. Moreover, the ion velocity data revealed that the ion flows moved toward west and toward lower latitudes. Based on these characteristics we infer that the heavy ions may originate from the sub-auroral latitudes (source region), where these heavy ions were driven by the poleward sub-auroral electric fields to drift westward and moved equator-ward to the lower mid-latitudes. ROCSAT-1 was nearby the source regions to observe the NO+ anomaly events. |
參考文獻 |
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吳忠益,磁暴時中緯度重離子異常現象之研究,碩士論文,國立中央大學太空科學研究所,2005。
網站
太空教室: http://www.ss.ncu.edu.tw/~SpaceEdu/
ROCSAT-1 and IPEI: http://csrsddc.csrsr.ncu.edu.tw/
Dst資料: http://swdcdb.kugi.kyoto-u.ac.jp/
Kp 資料:ftp://ftp.gfz-potsdam.de/pub/home/obs/kp-ap/
DMSP: http://www.saa.noaa.gov/nsaa/products/welcome http://www.ngdc.noaa.gov/dmsp/descriptions/dmsp_sensors.html
http://dmsp.ngdc.noaa.gov/html/availability.html |