| Title |
多地点落雷について |
| Author(s) |
高木, 渡辺, 有馬, 伊藤, 河崎, 仲野, 竹内, 木下, 鈴木, 斎川 |
| Journal |
電気学会論文誌B, 111, 1, 93-98 (1991) |
| Abstract |
Characteristics of lightning flashes with multiple strikes to the ground
within 1s are investigated, based on the data of video pictures of lightning
channels and the electric field changes. In winter, the occurrence frequency
of lightning flashes with multiple strikes to the ground is 55% which is
roughly twice as large as that in summer. The number of strike points in
winter is also larger than that in summer. The largest number of strike
points is 17 in winter, whereas 4 in summer. The polyphase fault on a power
transmission line in winter might be caused by a lightning flash of this
type. The average time intervals between strokes are less than 17 ms (one
TV field) in winter and 90 ms in summer respectively. The average distance
between strike points are 1.3 km in winter and 1.9 km in summer. |
| Title |
電磁界変化とUHF放射からみたロケット誘雷 |
| Author(s) |
金尾, 河崎, 松浦, 山本, 堀井, 仲野, 中村, 竹内 |
| Journal |
電気学会論文誌B, 111, 10, 1079-1084 (1991) |
| Abstract |
The electric field changes, the magnetic field changes, and UHF radiations
were observed during the rocket-triggered lightning experiment using the
4 channels transient memory of its sampling frequency of 1 MHz. The sensors
were a flat disk antenna, a loop antenna, and a disk corn antenna respectively.
Concerning the initiation of the electric and magnetic field changes, a
remarkable discrepancy between the rocket-triggered lightning to the tower
and the one to the ground is noticed. That is, the former is initiated by
a bipolar pulse of a large amplitude. On the other hand, the amplitude of
the latter increases gradually. Preceding such kind of changes, UHF isolated
pulses were also recorded. The statistics of the UHF isolated pulses are
presented. |
| Title |
冬季の送電線鉄塔へのトリガード落雷に伴う磁界変化 |
| Author(s) |
山本, 相木, 松原, 松浦, 河崎, 木下, 有馬, 竹内, 藤本 |
| Journal |
電気学会論文誌B, 112, 12, 1101-1109 (1992) |
| Abstract |
The magnetic field changes due to cloud-to-ground strokes have been measured
by loop antennas, which have been installed in the north-south direction
and the east-west direction, respectively, in winter and summer seasons
during 982 through 1989. In consequence of the measurements, it is found
that there is difference between the magnetic field change due to summer
lightning and that due to winter lightning, that is, the magnetic field
change measured by the N-S loop antenna is the same as the magnetic field
change measured by the E-W loop antenna in summer lightning, but not the
same in winter lightning (Winter lightning in this paper is the triggered
lightning initiated at the top of a steel tower of a transmission line.).
It is considered that the difference between the magnetic field change measured
by the N-S loop antenna and that by the E-W loop antenna in winter lightning
is caused by the anomalous shape of the lightning channel, such as the large
tortuosity of the channel close to the ground. The effects of the tortuosity
of the channel on the magnetic field change is shown by the numerical analysis
of magnetic field change due to the lightning stroke current, which propagates
along the tortuous channel. When the lightning stroke current is estimated
from the magnetic field change, it should be noted that the shape of the
channel has an important effect on the magnetic field change. |
| Title |
雷放電に伴う電界変化の時間同期多地点観測 |
| Author(s) |
牛尾, 王, 河崎, 松浦, 山本 |
| Journal |
電気学会論文誌B, 114, 11, 1160-1167 (1994) |
| Abstract |
Exploiting GPS systems, we synchronized three wideband (0.1Hz-2MHz) show
antennas with the time accuracy of 1ｵs. With this slow antenna system, we
recorded many lightning flashes at Hokuriku district area from December
2, 1993 to January 28, 1994. Almost all lightning flashes show consecutive
pulses superimposing on their slow field changes with the time intervals
of tens microseconds. We analyzed the arrival time difference of the pulses
to different stations and succeeded in locating the sources of the pulses
which are from PB (Preliminary Breakdown), L (Leader), R (Return stroke),
and C (Continuing current) stage for a positive cloud to ground discharge,
and from recoil streamers for a cloud discharge. Since we combine the functions
of traditional slow antennas with lightning location method, this paper
would provide a significant tool to study lightning physics, especially
the physics of the initiation of lightning. |
| Title |
シミュレーションによるレーザー誘雷の研究−不連続プラズマからの放電開始シミュレーション− |
| Author(s) |
古河, 内田, 島田, 安田, 山中, 河崎, 山中, 石窪 |
| Journal |
レーザー研究, 24, 5, 590-595, (1996) |
| Abstract |
We developed a simulation code on the discharges from discontinuous plasmas
to study laser triggered lightning theoretically. And the simulations of
the discharges with 2m gap from discontinuous plasmas, of which intervals
are 5mm or 10mm, are performed. The model is based on plasma approximation.
The effects of distortion of external electric field by tower and the progresses
of the leader are included. The speed of the progresses of the leader obtained
by simulations is about 3×106m/s which agrees with experimental results. |
