PLASMA-FILLED HELIX FOR A TRAVELING-WAVE AMPLIFIER.
Abstract
A plasma medium was used to increase the coupling between the electromagnetic fields of a helical slow-wave circuit and an electron beam of a traveling-wave tube amplifier. The sheath-helix model for the helix and a cold, collisionless plasma filling the interior of the helix were assumed in obtaining the dispersion diagrams and the beam coupling impedance. The axial d-c magnetic field was as important in this investigation as the plasma frequency. The experimental amplifier was operated in the frequency range of 2-4 GHz. It employed a beam-generated plasma with argon being the ionized gas. The maximum gain enhancement of the plasma-filled helix amplifier over the no-plasma case was 5 db. This was observed at frequencies above the plasma frequency but below the cyclotron frequency, where the theoretical enhancement was predicted to be 10-15 db. The upper frequency range of the amplifier was increased somewhat, but less than expected. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1967
- Accession Number
- AD0824923
Entities
People
- C. Kent Bullock
- Richard W. Grow
Organizations
- University of Utah