2001 Fiscal Year Final Research Report Summary
Research on laser triggered lightning for practical use
| Project/Area Number |
10355012
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
電力工学・電気機器工学
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| Research Institution | Insutitute for Laser Tecnolgy |
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Principal Investigator |
YAMANAKA Chiyoe Insutitute for Laser Tecnolgy, Director, 研究所長 (10028920)
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| Co-Investigator(Kenkyū-buntansha) |
UCIDA Sogeaki Insutitute for Laser Tecnolgy, Chief resercher, レーザービーム伝送研究チーム, 主任研究員 (20260177)
KAWASAKI Zen-ichiro Osaka University, Grduate school of engineering, professor, 大学院・工学研究科, 教授 (60126852)
YAMANAKA Tatsuhiko Osaka University, Institute of laser engineering, Director, レーザー核融合研究センター, 教授 (80107143)
SHIMADA Yoshinori Insutitute for Laser Tecnolgy, resercher, レーザービーム伝送研究チーム, 研究員 (80250091)
FUJITA Masayuki Insutitute for Laser Tecnolgy, Chief resercher, レーザー環境応用計測研究チーム, 主任研究員 (30260178)
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| Project Period (FY) |
1998 – 2001
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| Keywords | Laser triggered lightning / Success of laser triggered lightning / Discharge criteriawithplasma channel / CO2laser / UV laser / Irradiation timing / ACH mirror / Self-induced streamer |
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| Research Abstract |
Starting 1995 field experiments of laser-triggered lightning had been conducted on winter thunderstorms in Fukui, Japan. After a number of technical developments on laser system, thunderstorm monitoring devices and control system, the first laser-triggered lightning was achieved in 1997.This was a proof of the principle experiment of laser-triggered lightning which was followed by a technical development research program reported here. The target of the study was to improve success rate of triggering lightning. To approach the target, a new scheme of producing laser plasma channel for effective lightning induction was proposed and investigated in this study where strongly and weakly ionized plasma channels are generated to trigger and guide lightning discharges. The plasma channel used in the method is called Hybrid plasma channel. The method uses elongated weakly ionized plasma channel that guides the triggered lightning discharge high enough that it can extend to clouds by itself.
In
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the course of the present research project, conditions for the plasma channel to guide discharge have been clarified. The laboratory experiments had been conducted with use of a CO_2 laser, an UV laser (the fourth harmonic of Nd : YAG laser radiation) and a 1-MV impulse generator. It was concluded that a plasma density of 10^<13> cm^<-3> was required to firmly guide an electrical discharge along the plasma under an ambient electric field of thunderclouds. This plasma condition can be achieved by ionizing atmosphere by the IJV radiation.
Based on the results of the study, it can be considered that a combination of CO_2 and UV laser radiation and a reflecting mirror with multiple focusing points is a system for the field experiment of the next generation and hopefully a practical system.
Beside the laser system, a lightning prediction and auto-triggering system would improve the system performance since they can adjust the temporal window for plasma generation to effectively trigger lightning. Based on these elemental technologies, a new experiments for field test of laser triggered lightning can be designed. Less
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