Influence of helical electron beams on dynamics of waves in plasma-beam SFEL of dopplertron type

摘要

To investigate the device which is capable of generate and amplify audcoherent electromagnetic radiation in the millimeter and submillimeterudwavelength ranges is extremely important today. In the research underuddiscussion the model of a plasma-beam superheterodyne free electron laserud(SFEL) is the following. Plasma is located in the longitudinal focusingudmagnetic field with strength H0. Relativistic electron beam is injected intoudthis plasma environment at an angle α with respect to the magnetic fieldudstrength vector. We chose a circularly polarized intense low-frequencyudelectromagnetic wave as a pump. This wave propagates along the guidingudmagnetic field and in the opposite direction to the electron beam. Also weudfeed a weak high-frequency circularly polarized electromagnetic waveud(signal wave) into the system. The direction of the wave signal may beuddifferent, so the wave number can either positive or negative. Theudparametric resonance between the signal wave and the pump wave resultsudin excitation of a space-charge wave (SCW).