Three-dimensional analysis of the surface mode supported in Čerenkov and Smith-Purcell free-electron lasers

Kalkal, Yashvir; Kumar, Vinay

doi:10.1103/physrevaccelbeams.19.060702

Cited by 5 publications

(2 citation statements)

References 58 publications

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“…This change in the electron's energy is lowest for B 0 = 0 and is highest for B 0 = 20 kGs because the strong magnetic field keeps the electron focused and confines it well in the interaction region thereby allowing it to amplify the radiation. We anticipate, on the physical ground, that in CFELs with low output power, [32,39] the electron beam will not be influenced much by the radiation. In this regime, radiation is not strong enough to deviate the electron beam away from the interaction zone.…”

Section: Low Energy Beam and High Radiation Growthmentioning

confidence: 99%

“…In the theoretical investigation of a low power CFEL in Ref. [39], an axial magnetic field for the focusing of the electron beam was discussed but its effect on the dynamics of the beam has not been considered. This is of a greater importance in the case of high power CFEL with a flat dielectric slab,than in the case of the cylindrical dielectric waveguide, because of its strong asymmetric nature.…”

Section: Introductionmentioning

confidence: 99%

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Axial magnetic field effect in numerical analysis of high power Cherenkov free electron laser

Bazouband¹,

Maraghechi²

2019

Chinese Phys. B

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Cherenkov free electron laser (CFEL) is simulated numerically by using the single particle method to optimize the electron beam. The electron beam is assumed to be moving near the surface of a flat dielectric slab along a growing radiation. The set of coupled nonlinear differential equations of motion is solved to study the electron dynamics. For three sets of parameters, in high power CFEL, it is found that an axial magnetic field is always necessary to keep the electron beam in the interaction region and its optimal strength is reported for each case. At the injection point, the electron beamʼs distance above the dielectric surface is kept at a minimum value so that the electrons neither hit the dielectric nor move away from it to the weaker radiation fields and out of the interaction region. The optimal electron beam radius and current are thereby calculated. This analysis is in agreement with two previous numerical studies for a cylindrical waveguide but is at odds with analytical treatments of a flat dielectric that does not use an axial magnetic field. This is backed by an interesting physical reasoning.

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Section: Low Energy Beam and High Radiation Growthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Axial magnetic field effect in numerical analysis of high power Cherenkov free electron laser

Bazouband¹,

Maraghechi²

2019

Chinese Phys. B

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High‐Q Metallic Fano Metamaterial for Highly Efficient Cerenkov Lasing

Kim

Baek

Bhattacharya

et al. 2018

Advanced Optical Materials

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development of such CR-based applications is limited by thermal and dielectric breakdown issues. [3,4] Another limitation is that, due to the velocity threshold, large facilities are required to generate highly energetic particles. These limitations restrict the upper and lower size and performance boundaries in vital applications. Nowadays, metallic metamaterial devices have been proposed, which overcome the limitations of conventional Cerenkov devices to realize reversed CR from the negative-refractive index, [5] the ultralow threshold of kinetic energy in hyperbolic metamaterials, [6] and various metallic metamaterials comprised of subwavelength slits. [7][8][9] However, the realization of a high quality factor (Q) is still an outstanding roadblock for practical Cerenkov devices. Previous works on Cerenkov lasing (CL) using mirrors were limited by a lower electron beam impedance due to the interaction device and the radio-frequency (RF) coupling mechanism. [4,10] Here, to achieve a high Q for highly efficient CL, we focus on maximally trapping the electromagnetic Cerenkov radiation wave to extend its interaction with the electron beam and on controlling the radiation damping, as has been described in Rayleigh scattering to maximize the efficiency of CL. In this paper, we demonstrate that the interplay between an extremely low group velocity from the infinite transverse permittivity of the anisotropic metamaterials and the subradiant A high-quality-factor (high-Q) metallic Fano metamaterial is demonstrated both experimentally and theoretically. This material is suitable for highly efficient Cerenkov lasing in which subwavelength metallic slits are arranged to form asymmetric unit cells. In contrast to conventional dielectric Cerenkov or Smith-Purcell devices, in the proposed device, convection electrons traverse the high-Q metallic metamaterial. The interplay between an extremely low group velocity from the infinite transverse permittivity of the anisotropic metamaterial and the subradiant damping from a Fano-type slit mode is shown to be responsible for the high-Q value, which is measured to be unprecedented at 700. The resulting improvement in the Cerenkov lasing efficiency is estimated to be more than two orders of magnitude using a particle-in-cell simulation.

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Terahertz radiation source using a high-power industrial electron linear accelerator

Kalkal

Kumar

2017

Pramana - J Phys

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High power (∼ 100 kW) industrial electron linear accelerators (linacs) are used for irradiation applications e.g., for pasteurization of food products, disinfection of medical waste, etc. We propose that high power electron beam from such an industrial linac can be first passed through an undulator to generate powerful terahertz (THz) radiation, and the spent electron beam coming out of the undulator can still be used for industrial applications. This will enhance the utilisation of a high power industrial linac. We have performed calculation of spontaneous emission in the undulator to show that for typical parameters, continuous terahertz radiation having power of the order of µW can be produced, which may be useful for many scientific applications.

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Three-dimensional analysis of the surface mode supported in Čerenkov and Smith-Purcell free-electron lasers

Cited by 5 publications

References 58 publications

Axial magnetic field effect in numerical analysis of high power Cherenkov free electron laser

Axial magnetic field effect in numerical analysis of high power Cherenkov free electron laser

High‐Q Metallic Fano Metamaterial for Highly Efficient Cerenkov Lasing

Terahertz radiation source using a high-power industrial electron linear accelerator

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