A
brush discharge is an electrical
disruptive discharge similar to a
corona discharge that takes place between two
electrodes with a high
voltage between them, embedded in a nonconducting fluid, usually air. It is characterized by multiple luminous writhing
plasma streamers composed of ionized particles, which repeatedly strike out from the electrode, often with a crackling sound. The streamers spread out in a fan shape, giving it the appearance of a "brush".