Plasma effects on the free-electron laser gain with a plasma wave undulator

Abstract

Employing a magnetized plasma medium in the interaction region of a free-electron laser (FEL) offers the possibility of generating short wavelengths using moderate energy beams. Plasma in the presence of static magnetic field supports right and left circularly polarized electromagnetic modes. By superposition of these two modes, a linearly polarized electromagnetic mode is generated which can be employed as a plasma undulator in a FEL. This configuration has a higher tunability by controlling the plasma density on top of the γ-tubability of the conventional FELs. The roles of the axial magnetic field and plasma on the laser gain and the electron trajectories of an e-beam propagating through the plasma medium have been studied and new orbits of group (I, II, and III) have been found. Moreover, the stability of these orbits for different values of plasma frequencies has been investigated. It is shown that by increasing the axial guide magnetic field strength, the gain for orbits of group I trivially increase, while a decrease in gain has been obtained for orbits of group II and group III. In addition, it is found that with increasing the plasma frequency (or plasma density) the gain for orbits of group I and group II trivially decreases and shift to the lower cyclotron frequencies, while an increase in gain has been obtained for orbits of group III.

Terahertz radiation emission using plasma‐filled dielectric liner with the effects of pre‐modulated relativistic electron beam

“…[26,27] Antonsen et al [28] addressed the propagation of laser pulses in miniature non-uniform plasma channels due to the channel inhomogeneity and manifestation of guided waves, and achieved efficient excitation of the radiation. It also offers the possibility of using moderate-energy electron beams for obtaining high-frequency radiation.…”

“…It also offers the possibility of using moderate-energy electron beams for obtaining high-frequency radiation. [26,27] Antonsen et al [28] addressed the propagation of laser pulses in miniature non-uniform plasma channels due to the channel inhomogeneity and manifestation of guided waves, and achieved efficient excitation of the radiation.…”

Interaction of a relativistic dense electron beam with a laser wiggler in a vacuum: self-field effects on the electron orbits and free-electron laser gain

“…Although a great deal of attention has been focused on the laser-pumped FEL configuration in recent years, most treatments heretofore have neglected the influence of the equilibrium self-fields of the electron beam, especially in the FELs with a linearly polarized laser wiggler (Bacci et al, 2006;Mehdian et al, 2008;Sprangle et al, 2009;Olumi et al, 2011;Hasanbeigi et al, 2010;Jafari et al, 2014;Hedayati et al, 2015;Amri & Mohsenpour, 2016). It is known that space-charge effects are important in Raman FELs which operate at high electron density and low (relativistic) energy.…”