dorsal/arxiv
View SchemaSASE FEL with energy-chirped electron beam and its application for generation of attosecond pulses
| Authors | E. L. Saldin, E. A. Schneidmiller, M. V. Yurkov |
|---|---|
| Categories | |
| ArXiv ID | physics/0604165 |
| URL | https://arxiv.org/abs/physics/0604165 |
| DOI | 10.1103/PhysRevSTAB.9.050702 |
Abstract
Influence of a linear energy chirp in the electron beam on a SASE FEL operation is studied analytically and numerically using 1-D model. Explicit expressions for Green's functions and for output power of a SASE FEL are obtained for high-gain linear regime in the limits of small and large energy chirp parameter. Saturation length and power versus energy chirp parameter are calculated numerically. It is shown that the effect of linear energy chirp on FEL gain is equivalent to the linear undulator tapering (or linear energy variation along the undulator). A consequence of this fact is a possibility to perfectly compensate FEL gain degradation, caused by the energy chirp, by means of the undulator tapering independently of the value of the energy chirp parameter. An application of this effect for generation of attosecond pulses from a hard X-ray FEL is proposed. Strong energy modulation within a short slice of an electron bunch is produced by few-cycle optical laser pulse in a short undulator, placed in front of the main undulator. Gain degradation within this slice is compensated by an appropriate undulator taper while the rest of the bunch suffers from this taper and does not lase. Three-dimensional simulations predict that short (200 attoseconds) high-power (up to 100 GW) pulses can be produced in Angstroem wavelength range with a high degree of contrast. A possibility to reduce pulse duration to sub-100 attosecond scale is discussed.
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"abstract": "Influence of a linear energy chirp in the electron beam on a SASE FEL\noperation is studied analytically and numerically using 1-D model. Explicit\nexpressions for Green\u0027s functions and for output power of a SASE FEL are\nobtained for high-gain linear regime in the limits of small and large energy\nchirp parameter. Saturation length and power versus energy chirp parameter are\ncalculated numerically. It is shown that the effect of linear energy chirp on\nFEL gain is equivalent to the linear undulator tapering (or linear energy\nvariation along the undulator). A consequence of this fact is a possibility to\nperfectly compensate FEL gain degradation, caused by the energy chirp, by means\nof the undulator tapering independently of the value of the energy chirp\nparameter. An application of this effect for generation of attosecond pulses\nfrom a hard X-ray FEL is proposed. Strong energy modulation within a short\nslice of an electron bunch is produced by few-cycle optical laser pulse in a\nshort undulator, placed in front of the main undulator. Gain degradation within\nthis slice is compensated by an appropriate undulator taper while the rest of\nthe bunch suffers from this taper and does not lase. Three-dimensional\nsimulations predict that short (200 attoseconds) high-power (up to 100 GW)\npulses can be produced in Angstroem wavelength range with a high degree of\ncontrast. A possibility to reduce pulse duration to sub-100 attosecond scale is\ndiscussed.",
"arxiv_id": "physics/0604165",
"authors": [
"E. L. Saldin",
"E. A. Schneidmiller",
"M. V. Yurkov"
],
"categories": [
"physics.acc-ph"
],
"doi": "10.1103/PhysRevSTAB.9.050702",
"title": "SASE FEL with energy-chirped electron beam and its application for generation of attosecond pulses",
"url": "https://arxiv.org/abs/physics/0604165"
},
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