Terahertz electromagnetic wave generation and amplification by an electron beam in the elliptical plasma waveguides with dielectric rod

Abstract

The propagation of electromagnetic waves in an elliptical plasma waveguide including strongly magnetized plasma column and a dielectric rod is investigated. The dispersion relation of guided hybrid electromagnetic waves is obtained. Excitation of the waves by a thin annular relativistic elliptical electron beam will be studied. The time growth rate of electromagnetic waves is obtained. The effects of relative permittivity constant of dielectric rod, radius of dielectric rod, accelerating voltage, and current density of the annular elliptical beam on the growth rate and the frequency spectra are numerically presented.

Electromagnetic Waves Dispersion and Interaction of an Annular Beam-Ion Channel System in Plasma Waveguide

“…With the increasing of the inner radius (the ratio / ), the dispersion curves of the TM 01 modes will undergo slightly frequency shifts toward higher frequencies for both of the strong and weak ion channel and the upward shifts are more obscurely in strong ion channel case. In general, the EM eigenmode in an annular beam system has a higher phase velocity than the solid beam case with the same condition [22]. Therefore, the TM modes have higher frequencies for the solid case.…”

Novel mechanism for terahertz radiation by oblique colliding of two electron beams in plasma

“…Finally, it could be interesting to compare the performance of the THz source proposed in this article with other similar compact sources. A most typical contrast should be the Cherenkov devices based on plasma-filled slow wave structures [24][25][26]. For example, [25] considers an electron beam propagating in an elliptical waveguide with a beam voltage of 120-400 kV and a beam current of 10-100 A, which is comparable to the parameters considered in this paper.…”

“…The motion of the beam electrons at the intersection is governed by a linear dynamic equation and a linear continuity equation [24]…”

“…Recently, a new kind of high-power THz source, called electron beam-plasma system (EBPS) has attracted wide attention [16][17][18][19][20][21][22][23][24][25][26][27][28][29]. This THz source does not have a damage threshold as the plasma is in a highly ionized state.…”

“…Previous experiments have successfully observed powerful THz radiation from EBPS in a large magnetic confinement plasma device [16][17][18]. Meanwhile, various related THz radiation mechanisms have also been investigated [19][20][21][22][23][24][25][26][27][28][29]. It can be found that all the previous studies adopt linear schemes considering a single beam or two counterstreaming beams passing through a plasma column.…”