Simulation of the electron-ion ring kink instability

Simulation of the electron-ion ring kink instability, taking into account the nonlinear character of the polarization forces, has been carried out. It is shown that oscillations of the local electron and ion component center-of-masses are of the character of beats with amplitudes less than the beam dimensions. A singnificant velocity decrease of the instability development accompanied by the amplitude growth of the highest harmonics has been found. The results obtained well agree with experimental data