Whistler wave emission by a modulated electron beam on a metal-plasma boundary: near-field region

Transition and Cherenkov radiation in the near-fieid region of the thin radially restricted modulated electron beam injected to the plasma from the conductive plane along the magnetic fieid were calculated. It has been shown that the length of the wave excited by transition mechanism in the presence of constant magnetic field increases when plasma density decreases. The length of the wave excited on the second and third harmonics by Cherenkov mechanism decreases with the increasing of plasma density and beam modulation frequency. The obtained results are in a good agreement with experimental data.