Stimulated Raman scattering by an intense relativistic electron beam in a long rippled magnetic field

Journal Article · Mon Aug 01 04:00:00 EDT 1977 · Phys. Rev., A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.16.633· OSTI ID:7319365

Efthimion, P C; Schlesinger, S P

For the first time, the parametric coupling of the negative-energy cyclotron and space-charge modes to a fast coaxial waveguide structure is observed. The coaxial waveguide smooth center conductor is internally loaded to maintain a 5% ripple of 1.4-, 1.6-, or 2.0-cm periods on the background axial magnetic field throughout the interaction region of 70 cm. The parametric coupling may be considered a stimulated scattering process with the rippled magnetic field of zero frequency in the lab frame appearing as an electromagnetic pump wave in the beam frame, with 30-MW/cm/sup 2/ power density imparting to the electrons a quiver velocity V/sub os/ approx. = 0.1c. As predicted by theory, the frequency of the microwave radiation generated by the negative-energy cyclotron mode decreases with increasing magnetic /sup 6/ield while remaining constant for the negative-energy space-charge mode. Power levels from 1 to 5 MW have been measured at mm and cm wavelengths. Radiation at frequencies of 2..gamma../sup 2/V/L, where V and L are the beam velocity and ripple period, respectively, has been observed at high magnetic fields with an exponential-growth rate consistent with parametric coupling theory. This mechanism could be employed as a tunable generator of millimeter and submillimeter wavelength radiation.

• Research Organization: Plasma Physics Laboratory, Columbia University, New York, New York 10027
• OSTI ID: 7319365
• Journal Information: Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 16:2; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640301* -- Atomic
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMPLIFIERS
BEAM CURRENTS
BEAMS
BREMSSTRAHLUNG
CURRENTS
CYCLOTRON RADIATION
EFFICIENCY
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ELECTRONIC EQUIPMENT
EMISSION
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
KILO AMP BEAM CURRENTS
LEPTON BEAMS
MAGNETIC FIELDS
MASERS
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
MICROWAVE RADIATION
PARTICLE BEAMS
POWER RANGE 1-10 GW
POWER RANGE 1-10 MW
POWER RANGE 10-100 MW
POWER RANGE 100-1000 MW
RADIATION SOURCES
RADIATIONS
RAMAN EFFECT
RELATIVISTIC RANGE
STIMULATED EMISSION
WAVEGUIDES