Electrical Environment in a Storm Cloud

This article gives an overview of the electrical characteristics of the thundercloud and the predominant mechanisms that are at the origin. The specific cloud that can produce lightning is described and the parameters that control its development and its organization are discussed. According to the variety of the scales of time and space associated with the mechanisms that occur within the thundercloud, it is difficult to simulate them both  experimentally and numerically. Thus, the advances in the knowledge of the thunderstorm electricity have been sometimes relatively slow and have raised a lot of debates. Furthermore, in-situ observation remains difficult because of the hostility of the thundercloud medium for instrumentation, sensors, aircraft or other carriers of sensors. The responses to the questions in the domain of thundercloud electricity can sometimes remain speculative. However, recent detection techniques and laboratory experiments allow a better knowledge of the cloud electrical environment to be obtained. All aspects about lightning flashes and electrical discharges will be covered by other contributions in this issue.