雷放電画像観測用高時間分解カメラの開発

抄録

A new type of high-speed streak camera was developed to observe the process of lightning discharge. The camera consists of a rotating quadrate pyramid mirror and a digital video camera. Using the camera we can observe the lightning discharge in all horizontal direction and continuous observation is available without using high-speed shutter synchronizing with lightning discharge. The visual range, the time resolution and the dead time of the camera were evaluated theoretically and experimentally. From the evaluation we found that the time resolution of less than ten μs is expected at maximum rotating speed of the mirror of 200s^-1. The percentage of dead time was evaluated to be less than 50%. By using the camera, we have successfully observed the lightning discharges and from the observation we have evaluated the shape, and the duration of each lightning discharge.