DENSITY REGIMES FOR LOWER HYBRID WAVE COUPLING IN TOKAMAK PLASMAS
A detailed study of lower hybrid wave coupling in the Wega and Petula Tokamaks is presented in the light of a 2- D theoretical model with arbitrary density in front of the coupler. Different regimes can be distinguished theoretically depending on the value of this density relative to the cutoff density. At low densities coupling is mostly determined by the density gradient at the waveguide apertures. At moderate densities good matching is obtained between the "grill" antenna and the edge plasma, resulting in low reflection coefficients. When the density at the antenna gets higher, the plasma surface admittance must be slightly modified because of E x B currents. This effect removes the n-// = 1 singularity in the power spectrum and reduces the fraction of power radiated as surface waves.
Bibliographic Reference: WRITE TO CEA MENTIONING REPORT EUR-CEA-FC 1199 EN, 1983
Availability: Can be ordered online
Record Number: 1989122052200 / Last updated on: 1987-01-01
Available languages: en