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.

为了明确雷电接地击中的最终跳跃过程，我们研制了高速、高灵敏度雷电数字摄像机。该数码摄像机由多阳极光电倍增管、DC至50MHz带宽前置放大器、静态相机和多通道数字录像机组成。与旧相机相比，该相机具有一百倍的灵敏度、四倍的时间分辨率、两倍的空间分辨率和十六倍的动态范围。使用该相机已在夏季的岐阜大学和冬季的内田进行了四次闪电测量活动。我们获得了风车闪电接地击中的良好数据。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。两个数据均要可靠。(2)在雷电起始阶段，新相机的波形中有一些信号，而旧相机的波形中没有信号。这意味着新相机比旧相机更灵敏。（3）新相机的脉冲上升时间比旧相机短。（4）在上升先导启动之前，风车尖端有一些放电中风。