抄録
Lightning is discharge phenomenon between thunderclouds and the ground, or inside/between thunderclouds. However, a new type of atmospheric discharge was found in 1989 by chance: a discharge between thundercloud and ionosphere, named “sprites". After this discovery, similar types of transient luminous events in the middle and upper atmosphere, called TLEs, have been reported. On the other hand, gamma-ray flash radiated from the thundercloud, called TGF, was found in 1994 by satellite observation. Detail characteristics, mechanisms and effects on the atmosphere are not well understood both for TLE and TGF, although the extensive investigations have been carried out experimentally and theoretically for more than a decade. Here we review these phenomena and introduce the latest projects to solve the fundamental scientific problems.
