Collective effects on the operation of free-electron lasers with an axial guide field

Journal Article · Fri Oct 01 04:00:00 EDT 1982 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.26.2004· OSTI ID:6430683

Freund, H P; Sprangle, P; Dillenburg, D; da Jornada, E H; Schneider, R S; Liberman, B

The collective interaction in a free-electron laser with combined helical wiggler and uniform axial guide fields is presented in the linearized regime. The analysis involves a perturbation of the Vlasov-Maxwell equations about the constant-velocity helical trajectories, and the general driving currents are derived for this configuration. The complete dispersion equation is then obtained for a monoenergetic beam. Analytic solutions are obtained in the strong pump and space-charge dominated regimes, and an extensive numerical analysis is presented for wide range of operating parameters. The results indicate that substantial enhancements in the gain are possible when the relativistic axial gyrofrequency is comparable to the free-electron laser doppler upshift. In addition, there is a range of parameters for which the ponderomotive potential acts to destablize the electron beam. In this regime, we find both unstable electrostatic beam modes and largely electromagnetic modes with broad bandwidths.

• Research Organization: Naval Research Laboratory, Washington, DC 20375
• OSTI ID: 6430683
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 26:4; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
ELECTRICAL EQUIPMENT
ELECTROMAGNETS
ELECTRONS
ELEMENTARY PARTICLES
EQUIPMENT
FERMIONS
FREE ELECTRON LASERS
HELICAL INSTABILITY
INSTABILITY
INTERACTIONS
LASERS
LEPTONS
MAGNETIC FIELDS
MAGNETS
PLASMA INSTABILITY
PLASMA MACROINSTABILITIES
WIGGLER MAGNETS