Cherenkov radiation generated by a beam of electrons revisited

Cherenkov radiation generated by a beam of electrons is theoretically investigated. In the case that the boundary effect is negligible, coherent Cherenkov radiation does not depend on the longitudinal bunch form of the electron beam, which is remarkably different from other kinds of coherent radiation like coherent transition radiation and coherent synchrotron radiation. The reason for this result is ascribed to the criterion of the emission of Cherenkov radiation. The angular distribution of coherent Cherenkov radiation is mainly determined by the transverse bunch form of the beam. The spectral intensity of incoherent Cherenkov radiation is proportional to the velocity distribution function of the electrons in the beams. Based on these results, some methods are suggested to study hot electrons with the measurement of Cherenkov radiation. (C) 2005 American Institute of Physics.