LINEAR RESONANCE ANALYSIS OF BEAMS WITH INTENSE SPACE CHARGE IN THE UNIVERSITY OF MARYLAND ELECTRON RING (UMER)
Space charge can significantly affect the resonant properties of rings. The University of Maryland Electron Ring is a scaled experiment in which we have circulated beams with unprecedented intensities. Here we discuss the resonance analysis performed using the electrostatic particlein-cell code WARP, to understand the effect of space charge on the ring resonances. Beams with varying degrees of space charge in both the emittance-dominated and spacecharge-dominated regimes are attempted. The operating point is scanned to map the tune diagram under various lattice and injection errors. The results of the simulation study are compared to experimental measurements.
A nonconforming finite element method for a two-dimensional curl–curl problem is studied in this paper. It uses weakly continuous P1 vector fields and penalizes the local divergence. Two consistency terms involving the jumps of the vector fields across element boundaries are also included to ensure the convergence of the scheme. Optimal convergence rates (up to an arbitrary positive ∊) in both the energy norm and the L2 norm are established on graded meshes. This scheme can also be used in the computation of Maxwell eigenvalues without generating spurious eigenmodes. The theoretical results are confirmed by numerical experiments.