Penetration of slow waves into a dense plasma using a phased wave-guide array

We report experimental evidence of wave coupling and penetration to the interior of a high-density magnetoplasma using a double-waveguide antenna as a slow-wave structure. Reflection coefficients as low as 4% were observed. The experiment used 9 cm microwaves with a plasma of 11 cm diameter. The relevance to lower-hybrid heating of tokamak fusion plasmas is discussed. 11 refs.