OBSERVATION OF DRIFT-WAVE PROPAGATION AS A SOURCE OF TOKAMAK EDGE TURBULENCE

Core and edge turbulences were measured by Langmuir probe arrays in th e KT-5C tokamak plasma. The radial wavenumber spectra show a quasimode like structure which results in a net radial outward propagation of t he turbulent fluctuations. The measured fluctuation levels and wave ac tion fluxes are in good agreement with model predictions by Mattor et al., suggesting that drift wave propagation could be a source of edge turbulence.