Terahertz Cherenkov radiation induced by a self-modulated electron beam in plasma wakefield

Abstract

In this paper, a novel scheme of generating terahertz radiation is proposed, which considers a relativistic electron beam being modulated by its self-excited plasma wakefield in a plasma-filled slow-wave structure (SWS). Both the dispersion relation and the particle-in-cell simulation show that the self-modulation of the beam can act as a mode-selection method to excite the high-harmonics of the SWS and generate terahertz electromagnetic radiation. The present work gives a new thought for researching high-power and tunable terahertz sources.

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

“…On the other hand, the radiation frequency in this paper is 1 THz, which can be further enhanced by improving the local plasma density. Such a high frequency could be difficult to achieve by the plasma-filled Cherenkov sources even if beam modulation mechanism is introduced [28]. This is because the fundamental mode frequency is limited by the transverse boundary size of slow wave structures.…”

“…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.…”