Comments on the theory of radiation of relativistic particles in magnetic field and at the motion in transversal parabolic potential

Some features of relativistic particle radiation under condition when the length of the radiation formation is of the order or larger than the length of particle path in the magnetic field and at the motion in transversal parabolic potential are discussed. In particular, it is shown that at rotating the relativistic particle velocity in magnetic field on the restricted angle anti α the main high-frequency part of the synchrotron radiation is formed only, if the condition anti α > 1/γ, γ-Lorentz-factor of a moving particle, is fulfilled