Development of high speed and high sensitive digital video camera for lightning to theorize the reliable shielding method against lightning

研制高速高灵敏防雷数字摄像机，理论可靠的防雷屏蔽方法

• 批准号: 17560252
• 负责人: TAKAGI Nobuyuki
• 金额: $ 2.43万
• 依托单位: Gifu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560252/
• 关键词: final jump process; striking distance; connecting leader; lightning shield; video image of lightning progress; ファイナルジャンプ; コネクティングリーダ

To make clear the final jump process of lightning ground stroke, we developed a high speed and high sensitive digital video camera for lightning. This digital video camera consists of a multi-anode photomultiplier, DC to 50MHz bandwidth pre-amplifiers, a still camera and a multi-channel digital recorder. This camera has some performance with one hundred times sensitivity, four times time resolution, two times space resolution and sixteen times dynamic range compared with old one.Four lightning measurement campaigns using this camera have done at Gifu University in summer and at Uchinada in winter. We got a good data of lightning ground stroke to a windmill. From this data we found in the followings,(1) The waveform of the new video camera is very similar with that of the old video camera. Both data are to be reliable.(2) There are some signals in the waveform of the new camera in an initiation stage of lightning when the signal is nothing in the waveform of the old camera. It means the new one is more sensitive than old one.(3) The pulse rising time of the new camera is shorter than that of the old one.(4) There are some discharge from tip of the windmill before starting of an upward leader stroke.

为了清楚地了解雷击地面的最后跳跃过程，研制了一种高速、高灵敏度的雷电数字摄像机。该数字摄像机由多阳极光电倍增管、直流至50MHz带宽前置放大器、静态摄像机和多通道数字记录器组成。该相机具有100倍的灵敏度、4倍的时间分辨率、2倍的空间分辨率和16倍的动态范围等性能，并在岐阜大学夏季和内田冬季进行了4次闪电观测。我们得到了一个风车的雷击数据。从这些数据中我们发现：（1）新摄像机的波形与旧摄像机的波形非常相似。这两个数据都是可靠的。(2)在闪电的初始阶段，当旧相机的波形中没有信号时，新相机的波形中存在一些信号。这意味着新的比旧的更敏感。(3)新相机的脉冲上升时间比旧相机短。(4)在开始一个向上的先导冲程之前，风车的尖端有一些放电。