Analyses of superradiance and spiking-mode lasing observed at JAERI-FEL

R. Hajima, Nobuyuki Nishimori, R. Nagai, E. J. Minehara

Research output: Contribution to journalConference article

20 Citations (Scopus)


Japan Atomic Energy Research Institute (JAERI)-FEL has achieved quasi-CW lasing with an average power of 1.7kW, the initial goal of the R&D program. The FEL extraction efficiency obtained completely exceeds the well-known limit for non-bunched beam, which is determined by the number of undulator periods. We have conducted numerical studies to characterize lasing dynamics observed at JAERI-FEL. Cavity-length detuning curves numerically obtained show good agreement with experimental results. Lasing behavior numerically obtained exhibits chaotic spiking-mode and superradiance as the cavity-length detuning approaches zero. Broadening of lasing spectrum observed in the experiments is explained by these lasing dynamics. The extraction efficiency becomes maximal at the perfect synchronization of the cavity length, where the lasing is quasi-stationary superradiance. We also compare these results with analytical theory previously reported.

Original languageEnglish
Pages (from-to)270-275
Number of pages6
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Issue number1-3
Publication statusPublished - 2001 Nov 21
Event22nd International Free Electron Laser Conference (FEL 2000) - Durham, NC, United States
Duration: 2000 Aug 132000 Aug 18


  • Free-electron laser
  • Superconducting linac
  • Superradiance

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation

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