SUMMARY
The evolution in space and time of localized high-energy electromagnetic wave packets, which take place in processes of radiation by ultra relativistic electrons is considered. It is shown that high energies make stabilizing influence on the motion of such packets and that the lengths, within which their dispersion and reconstruction into the packets of diverging waves occurs, can be macroscopic. The electromagnetic field evolution in the process of ultra relativistic electron emission from substance into vacuum is considered. It is demonstrated, that in this case the electron can be in ‘half-bare’ state with considerably suppressed low frequency Fourier-components of the field around it during long period of time after the emission. It is shown that such state of electron can manifest itself in significant dependence of further ionization energy losses of the electron in thin plate situated in the direction of the particle motion on the distance between the plate and the scattering point.