NONLINEAR DYNAMICS OF CYLINDRICAL WAVES IN AN ISOTHERMAL PLASMA

Abstract

Within the framework of hydrodynamic description, the dynamics of nonlinear cylindrical Langmuir waves has been studied for an isothermal plasma where ions form a stationary background. The problem is considered in the electrostatic formulation for two-dimensional geometry. Using a partial, exact solution for the equations of hydrodynamics, a system of differential equations describing the dynamics of electrons with the finite temperature is obtained. In these calculations, a parabolic on radius, concave temperature profile associated with an electron density changing only in time was used. In the framework of this model, the influence of initial conditions and thermal effects on the regular dynamics of excited waves and the development of hydrodynamic singularities in the electron beam is discussed. Estimates are obtained that specify the permissible range of plasma parameters at which either regular wave behavior is realized or the electron wave breaks down. It is shown that the development of singular behavior due to the intrinsic nonlinearity can be avoided by taking into account the thermal effects and the initial rotation of electron beam. These results may be useful for establishing the mechanisms of nonequilibrium energy/momentum transfer in plasma media with finite electron and ion temperatures.

Estimations specifying the admissible range of plasma parameters are derived