Tohoku University Graduate School of Science
Tohoku University Graduate School of Science
Kagoshima National College of Technology
Tohoku University Graduate School of Science
出版者
宇宙航空研究開発機構宇宙科学研究本部
出版者（英）
Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA/ISAS)
雑誌名
第39回月・惑星シンポジウム
雑誌名(英)
Proceedings of the 39th ISAS Lunar and Planetary Symposium
ページ
25 - 28
発行年
2006-08-07
抄録（英）
For the purpose of confirming the plasma condition of the topside ionosphere, we have investigated spectra of Jupiter's radio emissions observed with the Cassini spacecraft to derive the Faraday rotation for the period of Cassini's Jupiter swing-by at the end of 2000. We have made the analyses especially for Io related Decametric radiation (Io-DAM) events since radio source locations of the events are considered to be in some limited areas and wave propagation paths for which plasma conditions are derived are easily determined. The results show that mean ionospheric plasma densities for Io-A and Io-B DAM events are about 6-20 and 3-10 elec./cu cm, respectively. This result suggests that (1) Jupiter's polar upper ionosphere where the Io-DAM waves propagate (about 15 to 30 thousands km above the ammonia cloud tops) is in a quite tenuous condition, and (2) The plasma density along the Io-B DAM rays (morning-side polar upper ionosphere) is more tenuous than that along the Io-A DAM rays (evening-side polar upper ionosphere).
Investigations of plasma environment of Jupiter's polar upper ionosphere by spectrum analysis of auroral radio emissions
