Paper  Title  Page 

TUPPC094  Experimental Observations of Largeamplitude Solitary Waves in Electron Beams  1377 


Funding: Work funded by the US Dept. of Energy Offices of Fusion Energy Sciences and High Energy Physics and Fusion Energy Sciences, and by the Dept. of Defense Office of Naval Research. The longitudinal dynamics of space charge dominated beams plays an important role in particle accelerators and other applications such as heavy ion fusion and free electron lasers (FELs). All beams are spacecharge dominated near the source. Furthermore, the longitudinal profile is not necessarily an ideal mathematical function. By means of experiments on the University of Maryland Electron Ring (UMER), we studied how a perturbation to the line charge density could affect the beam propagation. By varying the initial amplitude of the perturbation, we access nonlinear space charge physics. When starting with largeamplitude perturbations, we have observed, for the first time in charged particle beams, solitary waves for which the nonlinear steepening exactly balances the wave dispersion, leading to persistent waves that preserves their shape over a long distance. This paper presents the results of the soliton experiments, including systematic studies of the dependence of the soliton propagation on beam current, perturbation level and width. The data is compared with theory and simulation. 

WEPPR013  Design of an Electrostatic Extraction Section for the University of Maryland Electron Ring  2964 


Funding: This work is supported by the US Dept. of Energy Office of High Energy Physics. The University of Maryland Electron Ring (UMER) is a 11.5 meter circumference, 10 keV, electron storage ring dedicated to the study of the physics spacechargedominated beams transported over long path lengths. The intensity of the space charge in UMER can be varied by aperturing the injected beam current from 0.6 mA to 100 mA. Recently, the electron beam has been transported over one thousand turns. To fully characterize the transverse and longitudinal evolution of the beam on a turnbyturn basis, extraction and transport to a diagnostic station is required. We present the design of a pulsed electric extraction system that satisfies the challenging constraint of fitting the hardware within the dense magnet lattice. The extraction system must universally accommodate the range beam intensities and minimize any disruption to the circulating beam 

THPPR013  Beam Transport in Alternative Lattices at the University of Maryland Electron Ring (UMER)  3993 


Funding: This work is funded by the US Dept. of Energy Offices of High Energy Physics and High Energy Density Physics, and by the US Dept. of Defense Office of Naval Research and Joint Technology Office. We discuss the motivation, general procedure and results of first experiments of beam transport with two alternative focusing schemes at UMER, a lowenergy (10 keV), highcurrent (1100 mA) electron storage ring. The new ring optics simplifies injection and RMS envelope matching, and gives us a larger number of beam position monitors (BPMs) per (undepressed) betatron wavelength, all of which are desirable conditions for better orbit control. Furthermore, one of the new optics schemes is more symmetrical than the standard one, facilitating e.g. the implementation of quadrupole scans for betatron resonance studies. The alternative lattices also allow us to expand significantly on the tune parameter space available for the study of spacecharge dominated beam transport. 
