Stimulated emission processes from free electrons

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1980

OSTI ID:5482567

McMullin, W A

We first consider stimulated emission by a relativistic beam of electrons along the direction of motion for the cases in which the electrons are accelerated in a pump field that is either an electromagnetic wave, or TE cylindrical waveguide mode, or a transversely polarized, spatially periodic magnetic field with the emitted wave frequency Doppler upshifted from that of the pump field. This effect has been labeled a Free Electron Laser (FEL), and under the condition that the photon energy is much less than the electron kinetic energy, the amplification is found to be a classical effect and due to a Lorentz V x B or ponderomotive force bunching of the electrons. For a long interaction region a relativistic, linear dispersion relation describing the emitted radiation is derived by the kinetic equation method. Analytic gain expressions for emission from individual electrons or the beam plasma oscillations along with conditions on the pump field amplitude, beam density, and momentum spread of the beam for their validity are obtained. Next, we consider stimulated emission from a relativistic beam of electrons under acceleration in parallel, static electric and magnetic fields subject to the conditions that the photon energy and Landau orbital energy of the electrons in the magentic field are much less than the electron kinetic energy. The kinetic equation is linearized with respect to the emitted field amplitude and static electric field amplitude with the magnetic field taken into account exactly. The distribution function obtained from the kinetic equation is used to calculate the induced current driving the emitted field, and the induced current is used in the the wave equation for the emitted field from which the amplification is studied.

• Research Organization: California Univ., San Diego (USA)
• OSTI ID: 5482567
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
FREE ELECTRON LASERS
ANALYTICAL SOLUTION
ELECTRIC FIELDS
ELECTRON BEAMS
GAIN
KINETIC EQUATIONS
MAGNETIC FIELDS
STIMULATED EMISSION
AMPLIFICATION
BEAMS
EMISSION
ENERGY-LEVEL TRANSITIONS
EQUATIONS
LASERS
LEPTON BEAMS
PARTICLE BEAMS
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654001 - Radiation & Shielding Physics- Radiation Physics
Shielding Calculations & Experiments