| Project/Area Number |
13554015
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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 | 展開研究 |
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| Research Field |
Space and upper atmospheric physics
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
ARAKAWA Masahiko Hokkaido University, Inst. Low Temp. Sci., Inst., 低温科学研究所, 助手 (10222738)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Naoki Hokkaido University, Inst. Low Temp. Sci., Inst., 低温科学研究所, 助手 (50271531)
MAENO Norikazu Hokkaido University, Inst. Low Temp. Sci., Prof., 低温科学研究所, 教授 (50001657)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥13,700,000 (Direct Cost: ¥13,700,000)
Fiscal Year 2003: ¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2002: ¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 2001: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | lcy planets / Ice dust / Electrostatic accelerator / Impact experiment / Aggregates / High speed camera / Drag coefficient / Electric charge density / 静電加熱 / 衝突付着 / 衝突破壊 / 光電場 / 誘電分極 / 高速度撮影顕微鏡 / 静電場 / 凝縮 / 付着 / 電荷 |
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| Research Abstract |
We have developed an electrostatic accelerator to launch a ice dust and ice aggregates at a wide range of velocities from cm/s to km/s. The ice sample launched was prepared by a condensation, method : a cold copper plate cooled by liquid nitrogen was subjected to an air saturated with water vapor at -10℃. The condensed icy dust is an almost spherical shape with the size of 10 μm, Ice aggregates were grown by collecting each ice dust under high electric field more than 100 V/cm. The aggregate was charged under the electric field, so that it was launched by the electrostatic attraction. The relationship between the electric field and the velocity is derived as follows for the aggregates of 500μm.: V_i=0.25(V_<o>/d)^<0.9> (m/s), V_i: velocity, V_o: Voltage, d: distance between electrodes (d=2.5mm). The launch velocity is strongly affected by the air drag for the small aggregates, so we have set a vacuum chamber to eliminate the gas drag to the aggregates in the acceleration. We also used a longer acceleration tube to avoid disruption of the aggregates by the strong attraction force. As a result we have achieved 20m/s for 500μm aggregate at the electric field of 1kV/mm and 1 bar. In the evacuated condition of 0.1 bar, the launched velocity increased about 3 to 4 times higher than that of 1 bar at the same electric field strength. This means that it could be possible to achieve more than 100 m/s for ice aggregate of 500 μm at 1kV/mm.
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