| Project/Area Number |
05650287
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
電力工学・電気機器工学
|
|---|
| Research Institution | NUMAZU COLLEGE OF TECHMOLOGY |
|---|
Principal Investigator |
WAKAMATSU Masatoshi Nunazu C.of T., Electrical Engineering, Professor, 電気工学科, 教授 (40043145)
|
|---|
| Project Period (FY) |
1993 – 1994
|
| Project Status |
Completed (Fiscal Year 1994)
|
| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1993: ¥1,300,000 (Direct Cost: ¥1,300,000)
|
|---|
| Keywords | Thunder measurement / Winter lightning / Channel reconstruction / Channel altitude / Line sound source / Superposing simulation / 雷鳴 / 雷放電路の再現 / 音源高度 / ロケット誘雷 / 雷放電経路 / 対地雷撃雷 / 雲放電 |
|---|
| Research Abstract |
The shape of lightning channels can be reconstructed from the thunder signals measured with three microphones. This acoustic technique has the advantage of reconstructing the invisible lightning channels inside the colud by simple equipments. We have improved the accoustic method to reconstruct the channels from long duration thunder by the personal computer system. Experiments of artificial lightning triggered by a rocket have been carried out at Mt. Okushishiku with an altitude 928 m near Kamazawa, since the winter of 1987. We measured thunder data at Shishiku Heights located at 3.6 km north of the experiment site in 1993. Lightning channels were reconstructed from 7 winter thunder records. Then, it becomes clear that the mean hight of sound sources, e.i.the channel altitude is ranged between 1.5 km and 2.4 km and the horizontal distance is 4.4 km on the average.
Characters of line sound source are examined by superposing simulation of a presure wave generated from a spark discharge of 1mm gap-length. The calculated characteristics are compared with the experimental vales. The wave amplitude in the eqratorial plane of source is propotipnal to the spurce length. The wave length becomes longer according as the radiated angle from the perpendicular bisector increases. The thunder signals of the cloud discharge are different from those of the ground discharge that has a long line channel between the cloud and the ground. Therefore, the SN ratio of the ground discharge is larger than the cloud discharge.
|
