Coherent Cherenkov-cyclotron radiation excited by an electron beam in a two-spiral metamaterial waveguide
Abstract
We present the analysis of a microwave generator that uses two-spiral metamaterial (MTM) plates in a below cutoff WR340 waveguide that interacts with a high-power electron beam, motivated by recent results obtained by researchers at MIT. Particle-in-cell simulations using the MAGIC code demonstrated that power levels of 12 MW are achieved in a backward wave mode at a frequency of 2.47 GHz from an anomalous Doppler instability using a 1 μs pulsed electron beam of energy 400 keV, current 82 A in a 415 G magnetic field. In addition, a backward wave with 9 MW output power is achieved at a frequency of 2.54 GHz attributed to a Cherenkov instability using a 1 μs pulsed electron beam of energy 400 keV, current 82 A in a 1200 G magnetic field. MAGIC simulations demonstrate that the beam-wave interaction electronic efficiency can be as high as 27.4%. Nonlinear simulations indicate that beam interception leads to secondary electron emission from surfaces, which makes the anomalous Doppler instability and Cherenkov instability more complicated by a shift in frequency. This work seeks to clarify some discrepancy between particle-in-cell simulations and experiments at MIT over a range of guide magnetic field.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 01, 2018
- Source ID
- 10.1063/1.5049380
Entities
People
- Ahmed Elfrgani
- C. Liu
- Edl Schamiloglu
- M. I. Fuks
- M. Liu
- Sabahattin C. Yurt
Organizations
- Air Force Office of Scientific Research
- Office of Naval Research
- University of New Mexico
- Xi'an Jiaotong University