``Gas-dynamic'' expansion of a fast-electron flux in a plasma

The one-dimensional flight of a fast electron flux in plasma is investigated taking into account generation and absorption of plasma waves. The transition from the kinetic description to the gas dynamics is made. The closed set of gas dynamic equations for electrons and plasmons is derived and a solution is obtained in the case of monoenergetic injection of fast electrons. This solution represents the beam-plasma structure, which propagates in plasma with a constant velocity.