Superradiance in the high-gain free-electron laser

Journal Article · Sun Oct 15 04:00:00 EDT 1989 · Physical Review (Section) A: General Physics; (USA)

DOI:https://doi.org/10.1103/PhysRevA.40.4467· OSTI ID:5295178

Bonifacio, R; McNeil, B W.J.; Pierini, P ^[1]

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1. Dipartimento di Fisica, Universita di Milano, Via Celoria 16, 20133 Milano, Italy (IT)

In this paper we describe the effects of slippage on the single-pass high-gain free-electron laser (FEL) amplifier. We use a one-dimensional computational code to show the existence of two new dynamical regimes characterized by a dimensionless parameter {ital K}, which is a measure of the slippage in one gain length. We define the long-pulse limit to be when {ital K}{much lt}1 or the electron pulse length {ital L}{sub {ital e}} is much greater than a properly defined cooperation length'' {ital L}{sub {ital c}} ({ital L}{sub {ital e}}{much gt}L{sub c}). In this case we find that only the leading region of the propagating radiation pulse exhibits the usual steady-state behavior, with peak power proportional to {ital n}{sub {ital e}}{sup 4/3} (where {ital n}{sub {ital e}} is the electron-beam density). The trailing (slippage) region exhibits a spiking behavior with peak intensities reaching many times the saturated intensity predicted by steady-state theory. We define the short-pulse regime to be when {ital K}{approx gt}1 ({ital L}{sub {ital e}}{approx lt}L{sub c}). In this regime the peak power emitted by the electrons does not scale as {ital n}{sub {ital e}}{sup 4/3}, as predicted by steady-state theory, but scales as {ital n}{sub {ital e}}{sup 2}, which is typical of superradiant behavior. Furthermore, energy is extracted from the electrons in a continuous way, with no steady-state synchrotron oscillatory-type behavior.

• OSTI ID: 5295178
• Journal Information: Physical Review (Section) A: General Physics; (USA), Journal Name: Physical Review (Section) A: General Physics; (USA) Vol. 40:8; ISSN PLRAA; ISSN 0556-2791
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426002* -- Engineering-- Lasers & Masers-- (1990-)
AMPLIFICATION
AMPLIFIERS
ELECTRONIC EQUIPMENT
ELECTRONS
ELEMENTARY PARTICLES
EMISSION
ENERGY-LEVEL TRANSITIONS
EQUIPMENT
FERMIONS
FREE ELECTRON LASERS
GAIN
LASERS
LEPTONS
PHOTON EMISSION
PULSES
STIMULATED EMISSION
SUPERRADIANCE