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(Color) Synchrotron-undulator emission from an electron beam bunch: (a) incoherent emission of uncorrelated radiation wave packets (FEL spontaneous emission) l b > and (b) coherent emission of phase correlated wave packets (superradiant emission) l b .
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A formulation for the characterization of superradiant and stimulated-superradiant radiative emission from bunched electron beams is presented. The radiation is characterized in terms of power and spectral power per radiation mode, which provide a measure of the useful spatially coherent radiation power and spectral power emitted by a radiation sou...
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Context 1
... Each electron will emit in free space into the radiation mode a radiation wave packet of duration t s N w 2=!, where N w is the num- ber of undulator periods (or, more generally, the number of oscillations performed by the electrons). All of the wave packets are emitted and propagate in phase, constituting a superradiant emission process [see Fig. 2(b)]. The resultant superposition field of the wave packets, emitted by the electron bunch, is proportional to the number of electrons in the bunch N b , and therefore the radiated energy and instantaneous power are proportional to N 2 b . When condi- tion (2) is not satisfied, as is the case in conventional synchrotron-undulator radiation ...
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... 2(b)]. The resultant superposition field of the wave packets, emitted by the electron bunch, is proportional to the number of electrons in the bunch N b , and therefore the radiated energy and instantaneous power are proportional to N 2 b . When condi- tion (2) is not satisfied, as is the case in conventional synchrotron-undulator radiation [ Fig. 2(a)], the wave pack- ets interfere randomly. Their field average over all wave packets vanishes, and only their energies sum up in pro- portion to the number of electrons in the bunch N b . Consequently, the radiated energy and instantaneous power, emitted by the single bunch in the superradiance limit (2), is significantly larger (factor ...
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... of any radiation scheme can now be lucidly explained with the aid of Fig. 6, showing the superposition in complex plane of the amplitudes of modal wave packets, emitted by the individual electrons. Figure 6(a) shows the process of spontaneous emission: superposition of wave packets, emitted by uncorrelated electrons at random phases [compare to Fig. 2(a)]. When the electrons are injected at ...
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... Here we extend earlier theory of bunched-beam superradiance [1,3], and apply it to evaluate and optimize the spectrum and energy of a compact THz FEL shown schematically in Figure 1. This experimental setup is based on the design of the Israeli hybrid 6 MeV photocathode RF gun [4]. ...
... Bunched beam superradiance is an attractive concept for attaining intense THz radiation in a compact FEL scheme [1,3,[14][15][16]. Here we presented theory and design consideration of a superradiant waveguide FEL based on a compact (60 cm long) hybrid photocathode RF gun. ...
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