Accession Number : ADA190899

Title :   Enhanced Channel Tracking Due to Beam-Generated Magnetic Fields,

Corporate Author : MISSION RESEARCH CORP ALBUQUERQUE NM

Personal Author(s) : Welch, D R ; Godfrey, B B

PDF Url : ADA190899

Report Date : 10 Jun 1986

Pagination or Media Count : 45

Abstract : The complete frozen-field Maxwell equations are used to study the tracking behavior of an electron beam in a channel. The three type of channels considered contain conductivity, reduced density or a combination of both. The analytic work includes the derivation of the tracking force for a beam propagating entirely inside a square conductivity channel. The resulting expression reduces to E. Lee's electrostatic expression in the limit of small conductivity. However, for finite conductivity, magnetic tracking is dominant near the head of the beam, particularly for short rise-time beams. The numerical work using the three-dimensional simulation code IPROP shows high values for channel tracking with large optimal initial conductivities (roughly 1 * 10 to the 10th power scaler conductivity).For all three types of channels, tracking forces of or = 20 gauss are calculated for fast-rise 10-kA pencil beams in a 1-cm channel. Trumpet-shaped beams require larger channel radii to produce significant tracking. Forces of approximately 5 gauss are calculated for a 5-cm offset channel with 3-cm radius. This work suggests tracking forces may be an order of magnitude greater than previously thought.

Descriptors :   *CHANNELS, *ELECTRON BEAMS, *MAGNETIC FIELDS, *BEAM STEERING, CODING, DENSITY, ELECTROSTATICS, NUMERICAL METHODS AND PROCEDURES, RADIUS(MEASURE), REDUCTION, SIMULATION, THREE DIMENSIONAL, TRACKING, MAXWELLS EQUATIONS, ELECTRICAL CONDUCTIVITY

Subject Categories : Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE