Coherent emission from relativistic beam-plasma interactions

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:7055925

Latham, P E

A theoretical model for the production of high-power, high-frequency electromagnetic radiation from unmagnetized, relativistic beam-plasma interactions is studied. Emphasis is placed on the injected-beam system, for which the dominant portion of the radiation is emitted near the point where the beam enters the plasma. In such systems, frequencies much larger than the plasma frequency and power levels many orders of magnitude above that predicted by single-particle radiation have been observed experimentally. A two-step process is proposed to explain these observations: electrostatic bunching of the beam followed by coherent radiation by the bunches. The first step, beam bunching, produces large-amplitude electrostatic waves. A Green's function analysis is employed to understand the convective growth of those waves near the plasma boundary; their saturation amplitude is found by applying conservation of energy to the beam-plasma system. An azimuthally symmetric model is used to compute the saturated spectrum analytically, and a relatively simple expression is found. The second step, the interaction of the electron beam with the electrostatic spectrum, leads to the production of high-power, high-frequency electromagnetic radiation. From a detailed analysis of the phase-space evolution of the trapped beam, an analytic expression for the electromagnetic spectrum is found as a function of angle and frequency.

• Research Organization: California Univ., Berkeley (USA)
• OSTI ID: 7055925
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700103* -- Fusion Energy-- Plasma Research-- Kinetics
BEAM BUNCHING
BEAM DYNAMICS
BEAM-PLASMA SYSTEMS
COHERENT RADIATION
ELECTROMAGNETIC RADIATION
EMISSION
ENERGY RANGE
FUNCTIONS
GREEN FUNCTION
INTERACTIONS
MATHEMATICAL SPACE
PHASE SPACE
PLASMA WAVES
POWER DENSITY
RADIATIONS
RADIOWAVE RADIATION
RELATIVISTIC RANGE
SHORT WAVE RADIATION
SPACE