Superradiance driven by coherent spontaneous emission in a cherenkov free-electron maser amplifier

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Abstract

Superradiance (SR) initiated by coherent spontaneous emission (CSE) has been studied in a 35 GHz high gain free-electron Cherenkov maser. We present experimental results that show the development of ultra-short pulses of radiation in the non-linear superradiant regime which are characterised by a quadratic dependence of the intensity on the current. The self-similar pulses that develop have a duration that scales inversely with the fourth root of the intensity leading to three cycle long pulses at the highest intensity (few MW). The non-linear SR regime is preceded by a stage of linear exponential growth of the microwave pulses with a gain length of 1 cm. The superradiant pulse is shown to evolve from a CSE seed by extrapolating the growth curve. Further confirmation of CSE has been obtained by varying the current pulse shape. By varying the slope of the leading edge, and thus the Fourier components of the longitudinal spectral density, we are able to vary the strength of the CSE source. We compare the experimental results with a theoretical analysis.
LanguageEnglish
Pages261-266
Number of pages5
JournalNuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume445
Issue number1-3
DOIs
Publication statusPublished - 1 May 2000

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Superradiance
Masers
Spontaneous emission
masers
spontaneous emission
free electrons
amplifiers
Electrons
pulses
Spectral density
Ultrashort pulses
Seed
Microwaves
leading edges
high gain
Radiation
seeds
slopes
microwaves
cycles

Keywords

  • superradiance
  • free-electron laser Cherenkov radiation

Cite this

@article{d6e778d65f064d1ab18208476effeddb,
title = "Superradiance driven by coherent spontaneous emission in a cherenkov free-electron maser amplifier",
abstract = "Superradiance (SR) initiated by coherent spontaneous emission (CSE) has been studied in a 35 GHz high gain free-electron Cherenkov maser. We present experimental results that show the development of ultra-short pulses of radiation in the non-linear superradiant regime which are characterised by a quadratic dependence of the intensity on the current. The self-similar pulses that develop have a duration that scales inversely with the fourth root of the intensity leading to three cycle long pulses at the highest intensity (few MW). The non-linear SR regime is preceded by a stage of linear exponential growth of the microwave pulses with a gain length of 1 cm. The superradiant pulse is shown to evolve from a CSE seed by extrapolating the growth curve. Further confirmation of CSE has been obtained by varying the current pulse shape. By varying the slope of the leading edge, and thus the Fourier components of the longitudinal spectral density, we are able to vary the strength of the CSE source. We compare the experimental results with a theoretical analysis.",
keywords = "superradiance, free-electron laser Cherenkov radiation",
author = "D.A. Jaroszynski and Mark Wiggins and B.W.J. McNeil and G.R.M. Robb and P. Aitken and A.D.R. Phelps and A.W. Cross and K. Ronald",
year = "2000",
month = "5",
day = "1",
doi = "10.1016/S0168-9002(00)00080-2",
language = "English",
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pages = "261--266",
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TY - JOUR

T1 - Superradiance driven by coherent spontaneous emission in a cherenkov free-electron maser amplifier

AU - Jaroszynski, D.A.

AU - Wiggins, Mark

AU - McNeil, B.W.J.

AU - Robb, G.R.M.

AU - Aitken, P.

AU - Phelps, A.D.R.

AU - Cross, A.W.

AU - Ronald, K.

PY - 2000/5/1

Y1 - 2000/5/1

N2 - Superradiance (SR) initiated by coherent spontaneous emission (CSE) has been studied in a 35 GHz high gain free-electron Cherenkov maser. We present experimental results that show the development of ultra-short pulses of radiation in the non-linear superradiant regime which are characterised by a quadratic dependence of the intensity on the current. The self-similar pulses that develop have a duration that scales inversely with the fourth root of the intensity leading to three cycle long pulses at the highest intensity (few MW). The non-linear SR regime is preceded by a stage of linear exponential growth of the microwave pulses with a gain length of 1 cm. The superradiant pulse is shown to evolve from a CSE seed by extrapolating the growth curve. Further confirmation of CSE has been obtained by varying the current pulse shape. By varying the slope of the leading edge, and thus the Fourier components of the longitudinal spectral density, we are able to vary the strength of the CSE source. We compare the experimental results with a theoretical analysis.

AB - Superradiance (SR) initiated by coherent spontaneous emission (CSE) has been studied in a 35 GHz high gain free-electron Cherenkov maser. We present experimental results that show the development of ultra-short pulses of radiation in the non-linear superradiant regime which are characterised by a quadratic dependence of the intensity on the current. The self-similar pulses that develop have a duration that scales inversely with the fourth root of the intensity leading to three cycle long pulses at the highest intensity (few MW). The non-linear SR regime is preceded by a stage of linear exponential growth of the microwave pulses with a gain length of 1 cm. The superradiant pulse is shown to evolve from a CSE seed by extrapolating the growth curve. Further confirmation of CSE has been obtained by varying the current pulse shape. By varying the slope of the leading edge, and thus the Fourier components of the longitudinal spectral density, we are able to vary the strength of the CSE source. We compare the experimental results with a theoretical analysis.

KW - superradiance

KW - free-electron laser Cherenkov radiation

UR - http://dx.doi.org/10.1016/S0168-9002(00)00080-2

U2 - 10.1016/S0168-9002(00)00080-2

DO - 10.1016/S0168-9002(00)00080-2

M3 - Article

VL - 445

SP - 261

EP - 266

JO - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

T2 - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

JF - Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

SN - 0168-9002

IS - 1-3

ER -