1999 Fiscal Year Final Research Report Summary
Study on Jupiter's inner magnetosphere by the observation of Jovian synchrotron radiation
| Project/Area Number |
09440171
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
MORIOKA Akira Graduate School of Science, Tohoku University, Professor, 大学院・理学研究科, 教授 (50004479)
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| Co-Investigator(Kenkyū-buntansha) |
KOJIMA Masayoshi Solar-Terrestrial Environment Laboratory, Nagoya University, Professor, 太陽地球環境研究所, 教授 (70023687)
MISAWA Hiroaki Graduate School of Science, Tohoku University, Associate Professor, 大学院・理学研究科, 助教授 (90219618)
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| Project Period (FY) |
1997 – 1999
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| Keywords | synchrotron radiation / Jupiter's magnetosphere / Jupiter's radiation belt / energetic particles / Jovian radio waves / metric radio waves / relativistic particles / antenna |
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| Research Abstract |
1. The receiving system for the observation of Jupiter's synchrotron radiation has been developed. The developed pre-amplifier satisfies the demands of the minimum detection sensitivity of 0.1 Junsky and receiver noise temperature of 75 K.
2. The calibration system for the receiver, which is necessary to detect the accurate intensity of Jupiter's radiation, has been developed and completed. The phase and gain of the receiving system becomes to be calibrated using the loop method. The achieved compensation of the relative phase difference was less than 5.6, and relative gain was less than 0.2 dB.
3. The developed receiving and calibration system was connected to the large antenna system, and the performance test was carried out. It was confirmed that both the antenna beam width and receiving sensitivity satisfy the expected performance. The distribution map of the Galactic radio waves at a frequency of 327 MHz was successfully produces.
4. The simultaneous intensity variation of Jupiter's synchrotron radiation has detected using the radio telescopes of Kiso and Fuji Observatories, Nagoya University.
5. Detailed observations of Jovian synchrotron radiation was carried out using the 34 m large dish antenna. It was shown that the relativistic electrons were highly anisotropy during the radiation was enhanced. The correlation between the radiation and the solar 10.7 flux was also detected. A model simulation suggested that the observed radio flux enhancement was caused by the enhanced radial diffusion due to the intense solar UV/EUV event which heated the Jupiter's upper atmosphere.
6. Variations of energetic electrons released from the Jovian magnetosphere are investigated by using data from three spacecraft. Analyses confirmed that the Jovian electrons are modulated by the dynamic pressure of the solar wind at the position of Jupiter. It is also found that the release rate of energetic electrons is controlled by the polarity of IMF.
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