Free electron laser with longitudinal electric wiggler

Abstract

Excitation of a slow space-charge wave and a TM waveguide mode by passage of a relativistic electron beam through a static, spatially periodic, longitudinal electric field is investigated. The non-linear wave equation, free-electron-laser dispersion relation and spatial growth rate formula are derived in the laboratory reference frame. A formula for the energy-conversion efficiency based on saturation by electron trapping in the space-charge wave is also derived. Equations for transformation to the beam reference frame are presented. The results of a numerical study indicate that efficiencies of 25 to 60% and radiation wavelengths in the millimetre range are possible by operation near cut-off of the TM mode. Radiation wavelengths of the order of 100 mu m or less with somewhat lower efficiencies and growth rates may be obtained by operation above cut-off using a 1 cm pump wavelength

Free electron laser with longitudinal wiggler and finite axial magnetic field

“…This will result One may show that (6.7) and (6.8) reduce to results from previous work, e.g. Bekefi (11 and Willett et al [3] who considered the limit Bo+ m, and Willett and Hwang [4] who considered the electrostatic limit, by using the continuity equation instead of Poisson's equation (3.8) and Gauss' law (4.6).…”

“…In order to solve the non-linear wave equation for a three-wave interaction, some model for the wiggler is required. We shall assume an electrostatic, purely axial wiggler field with no radial dependence [3,4]. Thus, in the beam frame, we have g1 = -ikI@, exp[ik,(r + u o t ) ] i + cc (6.1)…”

“…The operative mechanism would consist of parametric decay of an electrostatic pump wave (which is propagating in the beam frame) into a forward-scattered space charge wave and a backscattered transverse magnetic (TM) waveguide mode. In previous thcorctical studies by Bekefi [l], Fenstermacher and Seyler [2] and Willett er a1 [ 3 ] , the axial magnetic field has been assumed to be sufficiently strong so as to render all electron motions purely axial. The primary objective of this study is to determine what effects would result from use of a somewhat weaker axial magnetic field in which perpendicular electron motions occur.…”

Syntheses, Crystal Structures, and Optical Properties of the Hexagonal Perovskites Variants ABX3 (B = Ni, A = Gu, FA, MA, X = Cl, Br; B = Mn, A = MA, X = Br)

“…[13] Up to now, only a few variants of the hexagonal perovskites have been structurally characterized for nickel halides with organic cations. Beside [N(CH 3 ) 4 ]NiX 3 (X = Cl, Br) [14] the crystal structure of MANiCl 3 [15] is found in literature.…”

Crystal structure of [(C2H5)3NCH3]Cu3Cl7: a new structural variant of the CuCl2 structure

“…The principal characteristic in the CuC12-based series, in addition to the ferrodistortive arrangement of the Jahn-Teller elongation, is the existence of edgesharing octahedra. In (RNH3)2CuX4 systems, an antiferrodistortive version of the layer perovskite structures is observed (Willett, 1964). The parent perovskite structures contain layers of corner-shared octahedra (Balz, 1953).…”