Measurement of DC Electric Field in Discharge Gap by Laser Spectroscopy
Project/Area Number |
11650292
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
電力工学・電気機器工学
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Research Institution | Miyazaki University |
Principal Investigator |
HONDA Chikahisa Faculty of Engineering, Miyazaki University, Professor, 工学部, 教授 (20037881)
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Co-Investigator(Kenkyū-buntansha) |
TSUJI Toshinori Faculty of Humanities, Miyazaki Municipal University Lecturer, 人文学部, 講師 (00254657)
SUNG Youl-moon Faculty of Engineering, Miyazaki University Res.Associate, 工学部, 助手 (50304837)
OTSUBO Masahisa Faculty of Engineering, Miyazaki University Ass.Professor, 工学部, 助教授 (90041011)
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Project Period (FY) |
1999 – 2000
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Project Status |
Completed (Fiscal Year 2000)
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Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,500,000 (Direct Cost: ¥2,500,000)
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Keywords | Laser-triggered lightning / Laser-produced plasmas / Discharge leader / Electric field / Laser spectroscopy / Stark effect / リーダー / レーザー蛍光法 / レーザー生成プラスヤ / 高速周波数掃引レーザー |
Research Abstract |
Laser-triggered lightning is a useful technique for protection against lightning strokes. However, the self-propagation of an upward leader along a laser-produced plasma channel is obstructed by the corona sheath at the top of the lightning tower under the DC electric field of thunderclouds. Therefore, it is important to measure the electric field in the space of corona discharge directly for determining the sheath region. The final goal of this research is to measure the electric field in the space above the lightning tower using a long plasma channel produced by a CO_2 laser and a coaxially introduced probe laser as a remote sensing technique. In the fiscal year 1999, we recognized Stark splitting in the spectrum of helium glow discharge by laser optogalvanic spectroscopy that showed a maximum field strength of about 3kV/cm and a sheath thickness of 2mm around the cathode. In the f.y. 2000, we adopted laser-induced fluorescence method (LIF) to observe the Stark spectrum in the same discharge system. The field strengths of 1.7-2.2kV/cm were obtained at the positions of 0.55-0.85mm above the cathode. In addition, we applied a DC field sensor with a Pockels element to measure the electric field in the space of corona discharges as a comparison. In a short gap of 10cm the sensor is required to be less than 2mm in diameter in order not to disturb the field. A rapid frequency scan laser does not observe stark profiles in a laser-produced plasma yet because of its malfunction. We will continue this study.
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Report
(3 results)
Research Products
(6 results)