Advanced Concepts for Photon Sources. Volume 5. Diamagnetism and Self-Field of a Pulsed Warm Beam in a Plasma Column.
Abstract
Diamagnetic loop signals from a plasma penetrated by an intense electron beam cannot always be interpreted simply as heating of the plasma. Any appreciable energy in beam gyromotion, for example, can cause a diamagnetic signal with a decay time long compared with the beam pulse duration (roughly six times faster than (tau sub D), the conventional magnetic diffusion time of the column); at late times the diamagnetic signal decays at the same rate as the azimuthal self-field, which allows one to determine (tau sub D), from the observed (B sub theta) pulse. In this work the Maxwell equations for a charge-neutral beam plasma system, coupled with a constitutive equation for the plasma, are analyzed. The resulting wave-diffusion equation for the induced azimuthal electric field is then solved approximately for the case of uniform scalar conductivity in the plasma column, and negligible conductivity outside the column. The azimuthal component of the primary beam current is modeled by physically reasonable radial profiles and pulse shape. Finally, problems introduced by time-variation of the conductivity are also given brief consideration.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1975
- Accession Number
- ADA015388
Entities
People
- J. Guillory
- V. Bailey