Breaking of a nonlinear wake wave excited by a laser pulse during its interaction with a semi-infinite plasma

Analytical methods are used to study the properties of a wake wave excited by a relativistic laser pulse passing through a blurred boundary of a homogeneous plasma. It is found that on the plasma density plateau near its boundary, the wake wave is not regular and its phase velocity depends on the spatial coordinate. It is shown that the breaking of a wake wave is a threshold process in terms of the electron oscillation energy; the influence of the transition layer parameters on the process of wake wave breaking is determined.