Synchronous motion of a relativistic particle in a wave propagating at an angle to a magnetic field

It is shown that there is a special regime of motion of a relativistic particle in a transverse or longitudinal wave propagating at an angle to a magnetic field, which is called synchronous and in which the condition for resonance of the particle with the wave is satisfied with increasing accuracy as the particle energy increases. In the synchronous regime of Cherenkov resonance a trend to unbounded acceleration is observed. © 1996 American Institute of Physics.