Streamer dynamics

Abstract

An analysis of streamers is presented from the viewpoint of the interplay of the rate processes that contribute to their development. The space-time evolution of a streamer front is described by a sequence of stages that are identified by the dominant rate process determining the local properties of the front and the ``turning point'' where this process is overcome by others. Numerical and analytical results are used to determine these stages. From this analysis, the properties of positive (cathode-directed) and negative (anode-directed) streamers are elucidated, in particular, the dynamics that lead to the saturation of electron-density and electric-field enhancement. An expression is obtained that relates the dynamics of the positive and negative streamers associated with an initial space-charge distribution.