Calculation and measurement of higher order mode losses in ITER ECH transmission lines
Author(s)Temkin, Richard J.; Bigelow, Timothy S.; Rasmussen, David A.; Woskov, Paul P.; Sirigiri, Jagadishwar R.; Shapiro, Michael; Tax, David Samuel; Kowalski, Elizabeth Joan; ... Show more Show less
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The ITER transmission lines (TLs) must be designed to deliver 20 MW from a 24 MW, 170 GHz gyrotron system. Miter bends are the main source of loss for these highly overmoded, corrugated, cylindrical waveguide TLs. Previous estimates have used only a pure HE[subscript 11] mode for the analysis of the loss due to a miter bend, however higher order modes (HOMs) must be considered for a practical analysis. For the linearly-polarized, Gaussian-like beam from a gyrotron, the LP[subscript mn] mode basis set should be used to describe the fields in the corrugated waveguide. The HOM content greatly affects the propagation of HE[subscript 11] content in a miter bend, with a large emphasis placed on the percentage of HOMs and the phase difference between HE[subscript 11] and each HOM. By considering LP modes, a complete basis set is used to investigate the HOM effects on HE11 loss in a miter bend. We also present a new conservation theorem relating the power centroid offset and propagation angle due to any two LP[subscript mn] modes propagating in the corrugated waveguide.
DepartmentMassachusetts Institute of Technology. Department of Electrical Engineering and Computer Science; Massachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Plasma Science and Fusion Center
34th International Conference on Infrared, Millimeter, and Terahertz Waves, 2009. IRMMW-THz 2009
Institute of Electrical and Electronics Engineers
Kowalski, E.J. et al. “Calculation and measurement of higher order mode losses in ITER ECH transmission lines.” Infrared, Millimeter, and Terahertz Waves, 2009. IRMMW-THz 2009. 34th International Conference on. 2009. 1-2. ©2009 Institute of Electrical and Electronics Engineers.
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INSPEC Accession Number: 10976905