摘要(英) |
Abstract
The ionospheric plasma and electrodynamics instrument (IPEI) onboard the ROCSAT-1 satellite consists of four sensors and a sensors potential circuit (SENPOT) on its aperture plane. The SENPOT is designed for minimizing the potential between the plasma and the sensor’s aperture plane to prevent from the surface potential effect on the ionized particles. The modulated potential by SENPOT varying with time is called the SENPOT potential. In this thesis, we use the SENPOT potential data to investigate the relationship between the satellite surface charging and the environmental conditions at low latitude ionosphere.
The surface current of the low-orbit and low-inclination spacecraft is dominated by ambient plasma current. Theoretically, SENPOT potential is strongly related to electron temperature. Unfortunately, ROCSAT-1 IPEI did not provide the in-situ measurements of electron temperature. However, by analyzing the other IPEI data we found that the SENPOT potential is strongly varying with the ion density. During the storm days, correlated violent changes were found among the ion temperature, ion drift velocity and the SENPOT potential. In the days when there were large solar flares, the ion density enhancements were frequently observed after the sunset hours. Similar changes with local time were found in the SENPOT potentials, with the peak SENPOT potential at about 1.8 hours after the local sunset. In addition, the fading of SENPOT potential is slower than that of the normal days. |
參考文獻 |
參考資料
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參考網頁
Keith.E.Holbert .,Spacecraft Charging, Arizona State University, http://www.eas.asu.edu/~holbert/eee460/spc-chrg.html
IPEI/SDDC HomePage:
http://csrsddc.csrsr.ncu.edu.tw
呂凌霄老師之太空科學教室:
http://www.ss.ncu.edu.tw/~lyu/lecture_files/2002Spring/IntroSpace_exam |