we derive error estimates in the appropriate norms, for the streamlinediffusion (sd) finite element methods for steady state, energy dependent,fermi equation in three space dimensions. these estimates yield optimal convergencerates due to the maximal available regularity of the exact solution.high order sd method together with implicit integration are used. the formulationis strongly consistent...

A program for simulation of the dynamics of high intensity charged particle beams in linear particle accelerators has been developed in C++ using the POOMA Framework, for use on serial and parallel architectures. The code models the trajectories of charged particles through a sequence of different accelerator beamline elements such as drift chambers, quadrupole magnets, or RF cavities. An FFT-b...

Title of Dissertation: LONGITUDINAL DYNAMICS OF AN INTENSE ELECTRON BEAM John Richardson Harris, Ph.D., 2005 Dissertation Directed By: Professor Patrick G. O'Shea, Department of Electrical and Computer Engineering The dynamics of charged particle beams are governed by the particles' thermal velocities, external focusing forces, and Coulomb forces. Beams in which Coulomb forces play the dominant...

For self-consistent ion-beam simulations including electron motion, it is desirable to be able to follow electron dynamics accurately without being constrained by the electron cyclotron timescale. To this end, we have developed a particle-advance that interpolates between full particle dynamics and drift motion. By making a proper choice of interpolation parameter, simulation particles experien...

Numerical simulation using particle-in-cell codes is a powerful tool in understanding the nonlinear dynamics of space-charge-dominated beams. The University of Maryland Electron Ring (UMER) will explore the transport of beams with intensity previously inaccessible to circular machines. The ring will also function as a testbed for accelerator codes. Applications such as heavy ion fusion and coll...

The latest designs of high-intensity proton rings require minimal beam loss. The major cause of losses in a circular machine is the interplay of excited resonances, leading to particle diffusion. Such resonances could be driven by the space charge itself, magnet errors or a combined effect of the above. As a result, the goal of achieving low-level beam loss becomes especially challenging in the...

This Letter reports the first observations of an anomalous hollow electron beam in the Duke storage ring. Created by exciting the single-bunch beam in a lattice with a negative chromaticity, the hollow beam consists of a solid core inside and a large ring outside. We report the detailed measurements of the hollow beam phenomenon, including its distinct image pattern, spectrum signature, and its...