Browsing by Author "Dewolf, David A."

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    Computer simulation of electron beams. I. Space charge algorithm for asymmetric beams
    Dewolf, David A. (American Institute of Physics, 1985)
    Longitudinal space_charge forces can be neglected in computer simulations of slowly curving quasilaminar electron beams. A particle mesh type algorithm for transverse space charge forces is developed, and great simplification in numerical calculation of asymmetric electron beams is demonstrated. Some typical examples for kinescope beams are discussed.
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    Computer simulation of electron beams. II. Low cost beam current reconstruction
    Dewolf, David A. (American Institute of Physics, 1985)
    Reconstruction of current density in electron beams is complicated by distortion of phase space which can require very fine discretization of the beam into trajectories. An efficient discretization of phase space is exploited, using conservation of charge and current in hypertriangle patches, to reconstruct the current density by fitting Gaussians through the distorted hypertriangles. Advantages and limitations are discussed.
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    Gaussian decomposition of beams and other functions
    Dewolf, David A. (American Institute of Physics, 1989-06-15)
    The Gabor expansion of a function f_(x) decomposes it into a double sum over integers m and n of a product of basis functions g(x_m X) and Fourier_series exponentials exp(2πi n/X) for given spacing X. The choice of basis function determines the coefficients a m n of the expansion. If f_(x) is band limited, the double sum can for all practical purposes be replaced by a single sum over Gaussian basis functions. This is extremely useful for expansion of multidimensional functions such as beams in phase space. Conditions of validity are given, and several examples illustrate the technique.