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  • Open Access

Tapering enhanced superradiance with a planar magnetic undulator

L. Feigin1,†, A. Gover2, R. Minnes1, and A. Nause1,*

  • 1Ariel University, Department of Physics, Ariel 4076414
  • 2Tel Aviv University, Center of Light-Matter Interaction, School of Electrical Engineering—Physical Electronics, Tel Aviv 69978, Israel

  • *Contact author: arieln@ariel.ac.il
  • †Contact author: leonf@ariel.ac.il
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Phys. Rev. Accel. Beams 28, 110702 – Published 19 November, 2025

DOI: https://doi.org/10.1103/ygzx-6my6

Abstract

Tapering enhanced superradiance (TES) is a novel radiation scheme that significantly improves the energy conversion efficiency in free-electron lasers. The undulator tapering design and optimization are crucial to the success of this efficiency boost and are fairly complicated tasks. Here, we demonstrate how to optimize the linear tapering rate using analytical magnetic field maps derived from pure permanent magnet (PPM) equations. A TES undulator (waveguided tapered undulator) is designed to operate at 0.5 THz at the zero-slippage regime, ensuring phase synchronicity and group velocity match between the electron beam and the radiation field. The superradiance condition is fulfilled by compressing the electron bunch to emit coherently. The results reveal a significant enhancement in energy conversion efficiency for both ideal and realistic beams. The real beam simulations use the ORGAD FEL parameters from the Schlesinger Accelerator Center at Ariel University. This work shows the potential of the TES method to achieve higher radiation energies through careful undulator design and optimized tapering and provides a complete model for this purpose.

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References (27)

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Phys. Rev. Accel. Beams 28, 110702– Published 19 November, 2025
  • Received 13 May 2025
  • Accepted 26 September 2025
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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