Computations on Relativistic Electron Beams and Rings.
Abstract
Numerical calculations of relativistic electron-beam phenomena are being performed at NRL to complement the experimental and theoretical investigations taking place there. The major advantage of computational techniques over other methods is the ability of the researcher to probe regimes not accessible experimentally, either because of cost or technology, and intractible analytically. A two-dimensional (r, z cylindrical) plasma-simulation code, CYLRAD, is being used in these investigations. In this code the relativistic trajectories of individual particles are integrated forward in time using the fully retarded self-consistent electromagnetic field of the entire collection of particles. CYLRAD has been used to study the expansion of non-neutral homogeneous beams with and without externally applied guide magnetic fields and the results agreed well with theory. These calculations are presently being extended to the treatment of partially and fully neutralized inhomogeneous beams where the onset of backstreaming will be studied. CYLRAD is also being applied to electron-ring configurations in support of the joint electron-ring-accelerator experiment currently under construction at the University of Maryland. In these latter calculations the collapse of an electron ring equilibrium due to ion loading is being investigated. In the presence of realistic transverse energy spread in the ring, calculations have shown that the pinching is accompanied by oscillations about the time dependent equilibrium and evaporation of thermally energetic electrons from the surface of the contracting ring. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1971
- Accession Number
- AD0728994
Entities
People
- Jay Paul Boris
- Roswell Lee
Organizations
- United States Naval Research Laboratory