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Title: Simulation of radial expansion of an electron beam injected into a background plasma

Technical Report ·
OSTI ID:6857528

A 2-D electrostatic particle code was used to study the beam radial expansion of a nonrelativistic electron beam injected from an isolated equipotential conductor into a background plasma. The simulations indicate that the beam radius is generally proportional to the beam electron gyroradius when the conductor is charged to a large potential. The simulations also suggest that the charge buildup at the beam stagnation point causes the beam radial expansion. From a survey of the simulation results, it is found that the ratio of the beam radius to the beam electron gyroradius increases with the square root of beam density and decreases inversely with beam injection velocity. This dependence is explained in terms of the ratio of the beam electron Debye length to the ambient electron Debye length. These results are most applicable to the SEPAC electron beam injection experiments from Spacelab 1, where high charging potential was observed.

Research Organization:
Southwest Research Inst., San Antonio, TX (USA)
OSTI ID:
6857528
Report Number(s):
N-90-15743; NASA-CR-186188; NAS-1.26:186188; TRN: 90-018055
Country of Publication:
United States
Language:
English