Fluctuations Do Matter: Large Noise-Enhanced Halos in Charged-Particle Beams
arXiv:physics/0306004 · doi:10.1103/PhysRevLett.91.264801
Abstract
The formation of beam halos has customarily been described in terms of a particle-core model in which the space-charge field of the oscillating core drives particles to large amplitudes. This model involves parametric resonance and predicts a hard upper bound to the orbital amplitude of the halo particles. We show that the presence of colored noise due to space-charge fluctuations and/or machine imperfections can eject particles to much larger amplitudes than would be inferred from parametric resonance alone.
13 pages total, including 5 figures