Оп the influence of radiation effects оп the beam instabllity

We examine radiative effects on the beam instability. It is shown that in contrast to the known results of beam-instability theory, taking the radiative friction of the electrons into account leads to the new result of an instability of the short-wavelength plasma oscillations ($ω_{p}<kV$). We obtain the radiative-friction corrections to the dispersion relations of waves whose phase velocity exceeds the thermal velocity of the electrons of the plasma and beam.