Two-stream instability in free electron lasers with a planar wiggler and an axial guide magnetic field

Mehdian, H.; Saviz, S.; Hasanbeigi, A.
April 2008
Physics of Plasmas;Apr2008, Vol. 15 Issue 4, p043103
Academic Journal
The linearized theory of two-stream free electron lasers (FELs) consisting of a relativistic electron beam transported along the axis of a planar wiggler in the presence of an axial guiding magnetic field is proposed and investigated. The dispersion relation is derived employing linear fluid theory. The characteristics of the dispersion relation are analyzed by numerical solutions. The results show that the growth rate is considerably enhanced on suitable ranges of normalized axial guiding magnetic field and normalized wave number. The effect of the difference between the velocities of the two beams, Δv=v1-v2, in this configuration of FELs is also considered and found that the growth rate is remarkably affected by velocity differences. It is also shown that the effect on the electrostatic mode is stronger than electromagnetic.


Related Articles

  • Self-field effects on small-signal gain in two-stage free-electron lasers. JAFARI, S; MEHDIAN, H; HASANBEIGI, A // Pramana: Journal of Physics;Mar2011, Vol. 76 Issue 3, p489 

    Self-field effects, induced by charge and current densities of the electron beam, on gain in two-stage free-electron laser with nonuniform guide magnetic field is presented. The gain equation for small-signal has been derived analytically. The results of numerical calculations show a gain...

  • Explicit expression for growth rates in free-electron lasers with helical and axial magnetic fields. Demokan, O.; Kabak, Y. // Physics of Fluids B: Plasma Physics;Oct92, Vol. 4 Issue 10, p3382 

    The dispersion relations of transverse and longitudinal modes in a free-electron laser with helical and axial magnetic fields are derived exactly for the one-dimensional case. The modes with positive and negative helicity are distinguished clearly. An analytically solvable expression for the...

  • The influence of the guiding magnetic field on the performance of a Smith–Purcell amplifier operating in the strong Compton regime. Schächter, Levi // Journal of Applied Physics;4/15/1990, Vol. 67 Issue 8, p3582 

    Presents a study which investigated the influence of the guiding magnetic field on the performance of a Smith-Purcell free-electron laser operating in the strong Compton regime. Discussion of electron dynamics; Information on the response function of the Smith-Purcell amplifier; Results.

  • The linear theory of the circular free-electron laser. Saito, H.; Wurtele, J. S. // Physics of Fluids (00319171);Jul87, Vol. 30 Issue 7, p2209 

    A small signal theory of a free-electron laser (FEL) with a rotating electron beam in a uniform axial magnetic field and in an azimuthal wiggler field (the ‘‘circular’’ FEL) is developed. The analysis includes the low and high gain regimes and the influence of...

  • The controlling parameter of a wiggler-pumped free-electron laser with an axial-guide magnetic... San-kui Gou // Physics of Plasmas;Feb95, Vol. 2 Issue 2, p533 

    Focuses on basic equations of a wiggler-pumped free-electron laser with an axial-guide magnetic field. Evolution of the configuration; Critical value of the controlling parameter which contains the effects of the wiggler, the electron beam, and the guide field; Evolution property of the...

  • Generation of electromagnetic radiation from a rotating electron ring in a rippled magnetic field. Yin, Y. Z.; Bekefi, G. // Physics of Fluids (00319171);Apr85, Vol. 28 Issue 4, p1186 

    Calculations show that modes resembling the free-electron laser (FEL) instability are excited when electrons move in quasicircular orbits under the combined action of a uniform axial magnetic field and an azimuthally periodic wiggler magnetic field. In.the model, a thin annular ring of rotating...

  • Electron beam transport in gas-loaded free-electron lasers. Yariv, Shalom; Friedland, Lazar // Physics of Fluids B: Plasma Physics;Dec90, Vol. 2 Issue 12, p3114 

    The effects of the presence of helical wiggler and axial guide magnetic fields on the quality of the electron beam in a gas-loaded free-electron laser are investigated. The electron velocity space diffusion theory in the free-electron laser is developed and tested in Monte Carlo simulations. The...

  • New class of unstable orbits of the equilibrium electrons in free-electron lasers. Zhang, Shi-Chang; Zhang, Zhong // Applied Physics Letters;10/2/1989, Vol. 55 Issue 14, p1380 

    We present a theoretical prediction of a new class of unstable orbits of the equilibrium electrons in free-electron lasers, which is entirely associated with the radial self-electric field and azimuthal self-magnetic field. It is also pointed out that these self-fields may deteriorate the beam...

  • Kinetic description of harmonic instabilities in a planar wiggler free-electron laser. Davidson, Ronald C. // Physics of Fluids (00319171);Jan86, Vol. 29 Issue 1, p267 

    The linearized Vlasov-Maxwell equations are used to investigate harmonic stability properties for a planar wiggler free-electron laser (FEL). The analysis is carried out in the Compton regime for a tenuous electron beam propagating in the z direction through the constant-amplitude planar wiggler...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics