Locations of Ion Ring Velocity Distributions Observed by THEMIS

• Main Authors: Ke-ChiaoChen, 陳科僑
• Other Authors: Sunny Wing-Yee Tam
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/40280098801118768542

碩士 === 國立成功大學 === 太空與電漿科學研究所 === 103 === In this study, we observe the ion ring velocity distributions in the magnetosphere by THEMIS satellite because of the low magnetic latitude orbits. We use Solid State Telescope (SST) to obtain the data and record the locations of the ring distributions in the magnetosphere at the distance less than 12 radii of the Earth. In our observations, we use radial distance, McIlwain L-parameter, magnetic latitude, and locations in GSM coordinates to analyze locations and calculate the occurrence probabilities of ion ring velocity distributions with the locations. We start to trace the time that ion ring distributions occurred and obtain to the corresponding satellite locations using by SSC 4D Orbit Viewer (TIPSOD), and calculate the probabilities in space. We also characterize the locations by regions, including dawn, dayside, dusk, and nightside, and discuss the occurrence probabilities of ion ring velocity distributions based on radial distance or McIlwain L-parameter and magnetic latitude. Ion ring distributions most often occur near and around the Earth (2RE to 4RE). The probabilities in nightside with specific region (L = 3, MLAT = 0° to 10°) are higher. The maximum value of probabilities is about 30% at the L=3 magnetic field lines. The probabilities of ring distributions have no big difference on each side when we consider L from 2 to 4.