| Paper | Title | Page |
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| TUP021 | Development of Powerful Long-Pulse Terahertz Band FELs Based on Linear Induction Accelerators | 91 |
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Funding: This work was supported by the Russian Scientific Foundation (RSCF), grant No. 19-12-00212. The paper is devoted to development of high-power long-pulse THz-band FELs based on new generation of linear induction accelerators which have been elaborated recently at Budker Institute (Novosibirsk). These accelerators generate microsecond electron beams with current at kA-level and energy of 2 to 5 MeV (with a possibility to increase electrons energy up to 20 MeV). Based on this beam, we initiated a new project of multi-MW long-pulse FEL operating in the frequency range of 1 to 10 THz using a wiggler period of 3 to 6 cm. For this FEL oscillator, we suggest a hybrid planar two-mirror resonator consisting of an upstream highly selective advanced Bragg reflector and a downstream weakly reflecting conventional Bragg reflector. Simulations demonstrate that the advanced Bragg reflector based on coupling of propagating and quasi-cutoff waves ensures the mode control at the values of the gap between the corrugated plates forming such resonator up to 20 wavelengths. Simulations of the FEL driven by electron beam generated by the LIU¿2 in the frame of both averaged approach and 3D PIC code demonstrate that the THz radiation power can reach the level of 10 to 20 MW. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP021 | |
| About • | paper received ※ 28 August 2019 paper accepted ※ 28 August 2019 issue date ※ 05 November 2019 | |
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| THP060 | Development of RF-Undulators and Powering Sources for Compact Efficient Compton FEL-Scattrons | 704 |
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| Conception of Compton-type FELs operating up to X-ray band is under development currently at IAP RAS (N.Novgorod). This concept is aimed at reducing energy of a driving relativistic electron beam and thereby increasing efficiency of the electron-wave interaction in FEL, as well as achieving relative compactness of the generator. The basis of this concept is RF-undulators of a new type - the so-called ’flying’ undulators. Results of current research of these RF-undulators, their simulations and ’cold’ tests in the Ka-band are presented. For powering RF-undulators spatially-extended narrow-band Cerenkov masers are developed in the specified frequency range. In order to achieve the required sub-gigawatt power level of the pumping wave in a strongly oversized oscillator, we exploit the original idea of using two-dimensional distributed feedback implemented in the 2D doubly-periodical slow-wave structures. The design parameters of Ka-band surface-wave oscillator intended for powering RF-undulators, results of its simulation and initial experimental studies are discussed. | ||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-THP060 | |
| About • | paper received ※ 15 August 2019 paper accepted ※ 25 August 2019 issue date ※ 05 November 2019 | |
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| TUP018 | Superradiant Emission of Electron Bunches Based on Cherenkov Excitation of Surface Waves in 1D and 2D Periodical Lattices: Theory and Experiments | 80 |
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Funding: The work was supported by RFBR grant no. 17-08-01072 In recent years, significant progress was achieved in generation of high-power ultrashort microwave pulses based on superradiance (SR) of electron bunches extended in the wavelength scale. In this process, coherent emission from the entire volume of the bunch occurs due to the development of microbunching and slippage of the wave with respect to electrons. An obvious method for generation of high-power sub-THz radiation is the implementation of oversized periodical slow-wave structures where evanescent surface waves can be excited. We report of the experiments on Cherenkov generation of 150 ps SR pulses with a central frequency of 0.14 THz, and an extremely high peak power up to 70 MW. In order to generate spatially coherent radiation in shorter wavelength ranges (including THz band) in strongly oversized waveguiding systems, we propose a slow wave structure with double periodic corrugation (2D SWS). Using the quasi-optical theory and PIC simulations, we demonstrate the applicability of such 2D SWS and its advantages against traditional 1D SWS. Proof of principle experiments on observation G-band Cherenkov SR in 2D SWS are currently in progress. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-FEL2019-TUP018 | |
| About • | paper received ※ 20 August 2019 paper accepted ※ 27 August 2019 issue date ※ 05 November 2019 | |
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