The Electron Bernstein Wave Emission Viewing System for the TJ-II Stellarator
- ORNL
- EURATOM-CIEMAT, Madrid, Spain
Efficient Electron Bernstein wave (EBW) mode conversion is important for heating dense plasmas in TJ-II. The O-X-B mode conversion scenario is being considered for heating high density (>1.3 x 10{sup 19} m-3) and NBI heated plasmas. Measurement of the thermal EBW emission from the plasma allows for a determination of the EBW mode conversion efficiency, and also provides an indication of the electron temperature evolution in overdense plasmas. A dual-polarized quad-ridged broadband horn will be used to measure the EBW emission at 28 GHz on TJ-II. Emission from the plasma is reflected from a steerable internal focusing mirror, propagates through a section of corrugated waveguide, and is then focused on the horn through a glass lens. A quarter wave plate, consisting of evenly spaced parallel metal plates, is used to help determine the degree of circular polarization. The field pattern from the horn-lens-waveguide combination has been measured as a function of horn-lens spacing and lens focal length with a 3-D scanning system in an effort to maximize coupling with the plasma. Details of the design, experimental results, and future plans will be presented.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 930809
- Resource Relation:
- Conference: 14th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, Santorini, Greece, 20060509, 20060512
- Country of Publication:
- United States
- Language:
- English
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