TY - CPAPER
AU - Gover, A.
AU - Emma, C.
AU - Friedman, A.
AU - Ianconescu, R.
AU - Musumeci, P.
TI - Conceptual Theory of Spontaneous and Taper-Enhanced Superradiance and Stimulated Superradiance
J2 - Proc. of FEL2015
AB - In the context of radiation emission from an electron beam Dicke's superradiance (SR) is the enhanced radiation emission from a pre-bunched beam. Stimulated Superradiance (ST-SR) is the further enhanced emission of the bunched beam in the presence of a phase-matched radiation wave. These processes were analyzed for Undulator radiation in the framework of radiation field mode-excitation theory[1]. In the nonlinear saturation regime the synchronism of the bunched beam and an injected radiation wave may be sustained by wiggler tapering [2]. Same processes are instrumental also in enhancing the radiative emission in the tapered wiggler section of seeded FEL[3]. In a long tapered wiggler the diffraction of the emitted radiation wave is not negligible even at Angstroms wavelengths (as in LCLS). A Fresnel diffraction model was provided in [4] for the SR process only. Here we outline the fundamental physical concepts of Spontaneous Superradiadce (SR), Stimulated Superradiance (ST-SR), Taper-Enhanced Superradiance (TES) and Taper-Enhanced Stimulated Superradiance Amplification (TESSA), and compare their Fourier and Phasor formulations in the radiation mode expansion and free-diffraction models. Detailed further analysis can provide better design concepts of high power FELs and improved tapering strategy for enhancing the power of seeded short wavelength FELs
PB - JACoW
CY - Geneva, Switzerland
SP - 746
EP - 751
KW - radiation
KW - electron
KW - wiggler
KW - FEL
KW - free-electron-laser
DA - 2015/12
PY - 2015
SN - 978-3-95450-134-2
DO - 10.18429/JACoW-FEL2015-WEP085
UR - http://accelconf.web.cern.ch/AccelConf/FEL2015/papers/wep085.pdf
ER -