Investigation of betatron instability in a wiggler pumped ion-channel free electron laser

Raghavi, Afzal; Mehdian, H.

doi:10.1088/0741-3335/53/10/105010

Cited by 4 publications

(1 citation statement)

References 11 publications

(27 reference statements)

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“…In recent years, much effort has been expended in the investigation of ion-channel pumped FELs [9][10][11][12][13]. The technique of ion-channel guiding has emerged as an effective method for focusing the electron beam; a relativistic e-beam injected into an underdense plasma (the plasma density is less than the beam density) can expel the plasma electrons outward to create an ion-channel, which has ideal focusing properties for e-beams.…”

Section: Introductionmentioning

confidence: 99%

Free-electron laser with a plasma wave wiggler propagating through a magnetized plasma channel

Jafari¹,

Jafarinia²,

Mehdian³

2013

Laser Phys.

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A plasma eigenmode has been employed as a wiggler in a magnetized plasma channel for the generation of laser radiation in a free-electron laser. The short wavelength of the plasma wave allows a higher radiation frequency to be obtained than from conventional wiggler free-electron lasers. The plasma can significantly slow down the radiation mode, thereby relaxing the beam energy requirement considerably. In addition, it allows a beam current in excess of the vacuum current limit via charge neutralization. This configuration has a higher tunability by controlling the plasma density in addition to the γ-tunability of the standard FEL. The laser gain has been calculated and numerical computations of the electron trajectories and gain are presented. Four groups (I–IV) of electron orbits have been found. It has been shown that by increasing the cyclotron frequency, the gain for orbits of group I and group III increases, while a decrease in gain has been obtained for orbits of group II and group IV. Similarly, the effect of plasma density on gain has been exhibited. The results indicate that with increasing plasma density, the orbits of all groups shift to higher cyclotron frequencies. The effects of beam self-fields on gain have also been demonstrated. It has been found that in the presence of beam self-fields the sensitivity of the gain increases substantially in the vicinity of gyroresonance. Here, the gain enhancement and reduction are due to the paramagnetic and diamagnetic effects of the self-magnetic field, respectively.

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Section: Introductionmentioning

confidence: 99%

Free-electron laser with a plasma wave wiggler propagating through a magnetized plasma channel

Jafari¹,

Jafarinia²,

Mehdian³

2013

Laser Phys.

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Influence of finite radial geometry on the growth rate of ion-channel free electron laser

2013

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The influence of finite radial geometry on the instability of a tenuous relativistic electron beam propagating in an ion-channel in a waveguide is investigated. The instability analysis is based on the linearized Vlasov-Maxwell equations for the perturbation about a self-consistent beam equilibrium. With the help of characteristic method the dispersion relation for the TE-mode is derived and analyzed through the numerical solutions. It is found that the positioning of the beam radius Rb relative to the waveguide radius Rc, and the ion-channel frequency can have a large influence on the maximum growth rate and corresponding wave number.

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Coupling Instability of a Warm Relativistic Electron Beam with Ion-Channel Guiding

Rostami¹,

Hajisharifi²,

Mehdian³

et al. 2019

Commun. Theor. Phys.

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In this paper, the coupling instability of warm relativistic electron beam (WREB) propagating through the ion channel guiding is investigated in detail. Obtaining the equilibrium state of the system by considering the self-electric and azimuthal magnetic field, the fluid-Maxwell equations as well as linear perturbation theory are employed to derive the dispersion relation of the excited modes in the system. Numerical analysis of the obtained dispersion relation shows that the electromagnetic (EM) instability can be induced nearly the center of the beam through coupling between the fast electron plasma wave (FEPW), originated from the longitudinal oscillation of WREB, and fast forward electromagnetic wave (FFEW). In this sense, growing the perturbation amplitude occurs due to transport the kinetic energy of WREB to the EM wave at the specific frequency range, where the phase velocity of FEPW and FFEW is coincided. The results of the present investigation will greatly contribute to the understanding of the stability of the warm relativistic electron beam in laboratory experiments, such as in free electron laser experiments, where the ion-channel guiding is used to confine the electrons against the self-repulsive forces generated by the beam itself.

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Investigation of betatron instability in a wiggler pumped ion-channel free electron laser

Cited by 4 publications

References 11 publications

Free-electron laser with a plasma wave wiggler propagating through a magnetized plasma channel

Free-electron laser with a plasma wave wiggler propagating through a magnetized plasma channel

Influence of finite radial geometry on the growth rate of ion-channel free electron laser

Coupling Instability of a Warm Relativistic Electron Beam with Ion-Channel Guiding

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