Nonlinear electron beam guiding by a reduced-density channel

Abstract

Suggested by numerical simulations, recent experiments have shown that a significant guiding force is exerted by a reduced-density channel on electron beams propagating through initially un-ionized air. A theoretical analysis of this guiding force had been given that assumed uniform beam and channel and small beam-channel offset. From a 2-D model, relative to a beam slice, the guiding force is calculated in this article for arbitrary beamchannel offset and for various smooth beam and channel profiles. This calculation confirms the above-quoted experimental evidence of a guiding force significant with respect to the deflection force exerted by the earth's magnetic field. It also confirms the crucial role played by the secondary electron temperature distribution. Finally, it suggests optimal values for the ratio between channel and beam rms radii.

Resistive hose growth of intense ion beams propagating in air

“…(26) was solved using a Bennett conductivity profile to obtain 0 0:693 and distance to peak growth Z=T 6:34, in close agreement with Lee's results from Eq. (19). We note that the conductivity model previously mentioned predicts a profile more like a Lorentzian (square root of the Bennett) in the body of the beam.…”

“…where C 0 is a constant and 0 is the maximum of the imaginary part of for all real K in Eq. (19). Lee finds 0 0:6902 for K r 0:5218.…”