Stability Regimes in a Helical Quadrupole Focusing Accelerator - Theory and Simulation
Abstract
The inclusion of helical quadrupole (stellarator) and axial guide fields in high current spiral line or recirculating accelerator configurations provides a high tolerance to energy mismatch and confines the beam against space charge forces. In such a configuration the electron beam can interact with the external fields and with electromagnetic waveguide modes such that the beam centroid can be (1) orbit unstable independent of the waveguide modes, (2) three-wave unstable or (3) fully stable. The various stability conditions are presented in the limit of zero beam current. These stability conditions are found to be good predictors of particle simulation results, with minor departures being observed at high current. Linearly unstable modes, obtained via numerical solutions of the dispersion relation, were observed in each simulation. Nonlinear behavior, such as mode saturation in some regimes, was also observed.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 04, 1990
- Accession Number
- ADA221755
Entities
People
- Chai AMei Tang
- Glenn R. Joyce
- Jonathan F. Krall
- Phillip A. Sprangle
Organizations
- United States Naval Research Laboratory