Experimental study on evolution of a nonlinear wave excited by a modulated electron beam in a plasma

The spatial evolution of the anharmonic profile of the electric-field wave in a beam-plasma system is investigated experimentally and the dynamics of the electron bunches is discussed on the basis of the experimental results. The variability of the structure of the bunches, and in particular, the breaking up of the bunches, which was previously predicted theoretically, is observed. It is found that the distortion of the initial profile of the wave becomes more severe as the ratio of the modulation frequency to the plasma frequency decreases. Direct experimental data are obtained on the high-frequency radial fields in the system