Chaos in an ion-channel free-electron laser with realistic helical wiggler

Abstract

Chaotic behavior of an electron motion in a free-electron laser with realistic helical wiggler and ion-channel guiding is studied using Poincaré surface-of-section maps. The effects of a realistic electron beam density on chaotic electron dynamics are investigated by considering an electron beam with Gaussian density profile in radial distance. The effects of self-fields on chaotic electron dynamics are investigated for different Gaussian beam parameters, and the results are compared with those of uniform electron beam. It is shown that the electron chaotic behavior can be controlled by changing the Gaussian beam parameter. Also, the chaotic behavior can be controlled by increasing the ion-channel and/or the electron beam densities.

Comparative study of electron motion and stability for different focusing regimes in a free-electron laser with three-dimensional helical wiggler

“…As an electron beam is formed by a great number of electrons, the quality of electron-beam transport must be related to the motion and stability of each single electron. In the previous literature, electron motion and stability have been studied for natural focusing, magnetic focusing and electric focusing regimes, (Benettin, Galgani & Strelcyn 1976;Blewett & Chasman 1977;Marshall 1985;Martin et al 1985;Takayama & Hiramatsu 1988;Whittum 1990;Conde & Bekefi 1991;Ozaki et al 1992;Abarbanel et al 1993;Jha, Kumar & Pande 1999;Esmaeilzadeh, Mehdian & Willet 2001;Zhang & Elgin 2004;Huang & Kim 2007;Raghavi, Ninno & Mehadian 2008;Rouhan & Maraghechi 2009;Ruan et al 2011;Socol et al 2011;Esmaeilzadeh & Taghavi 2012;Huang et al 2012;Maier et al 2012;Mehdian, Alimohamadi & Hasanbeigi 2012;Saviz, Rezael & Aghamir 2012;Bahman & Maraghechi 2013;Wang et al 2013;Xu et al 2013;Zhang 2013). In this paper we concentrate on a comparison of electron motion and stability for different focusing regimes.…”

Power enhancement via an ion-channel in a Raman free-electron laser

“…Compared to other plasmaloaded radio frequency devices, where external magnets are used, the advantage of ion-channel guiding, instead of the guide magnetic field, is that it cuts off the facility manufacture and operation expenses. Since the proof-of-principle experiments of the so-called ion-channel guiding FELs were made [26,27], a lot of papers have been devoted to this aspect, discussing the ion-hose instability, harmonic generation, satur ation mechanism, two-beam radiation, focusing peculiarity, electron's equilibrium orbits, motion chaos, beam temper ature effect, etc [28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

Effect of normalized plasma frequency on electron phase-space orbits in a free-electron laser

“…So far, a number of papers have been devoted to the study of the electron motion. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Evidently, exploring the ways to irregulate phase-space orbits is of significance in improving the electron-beam transport quality and the FEL performance. Recent studies indicate that there are several ways to cause electron irregular motion and in consequence, what might be termed 'FEL chaos' has been found.…”

“…[11] Irregular and chaotic electron motion could occur in an FEL with an electromagnetic-wave wiggler, or in an FEL with an ion-channel guide field. [12][13][14] In previous articles where the chaotic behaviors of electrons were discussed, the restriction was often made that the FEL wave field could be excluded, or regarded as constant or not self-consistent. Also, the effect of the beam plasma frequency on the electron motion was ignored.…”