2002 Fiscal Year Final Research Report Summary
Study on antenna characteristics for wave observation including kinetic effects of space plasma
| Project/Area Number |
12440131
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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 | Kyoto University |
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Principal Investigator |
USUI Hideyuki Kyoto University, Radio Science Center for Space and Atmosphere, Associate professor, 宙空電波科学研究センター, 助教授 (10243081)
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| Co-Investigator(Kenkyū-buntansha) |
KOJIMA Hirotsugu Kyoto University, Radio Science Center for Space and Atmosphere, Associate professor, 宙空電波科学研究センター, 助教授 (10215254)
OMURA Yoshiharu Kyoto University, Radio Science Center for Space and Atmosphere, professor, 宙空電波科学研究センター, 教授 (50177002)
MATSUMOTO Hiroshi Kyoto University, Radio Science Center for Space and Atmosphere, professor, 宙空電波科学研究センター, 教授 (00026139)
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| Project Period (FY) |
2000 – 2002
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| Keywords | computer experiments / space plasma / antenna characteristics / electromagnetic particle simulation / antenna impedance / plasma sheath / photo-electrons / plasma waves |
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| Research Abstract |
The objectives of the current study is to acquire the quantitative understanding of antenna characteristics in a magnetized space plasma by performing three-dimensional electromagnetic PIC simulations, which will be helpful designing the antenna onboard the future scientific satellite. We first examined the plasma sheath effect to the antenna impedance. We found that the sheath effect on the antenna impedance become weak when the radius of ion sheath formed around the antenna in the isothermal plasma becomes large. Next, we studied a case in which photo-electrons are emitted from the antenna surface. It is found that antenna impedance is affected at the frequency corresponding to the high density of photo-electrons in the vicinity of antenna. We finally examined a hot plasma case and found that the resonance at the plasma frequency becomes less sharp. Another important factor in the antenna characteristics is the effective length which is related to the current distribution along the antenna. In the receiving mode of antenna, however, the current distribution depends on the load impedance attached to the antenna and therefore the effective length may be modified. We will examine the dependency of the effective length on the load impedance as well as the plasma environment including plasma sheath, photo-electron emission, and finite temperature of plasma by performing EM-PIC simulations.
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