Drift wave antenna excitation in TORPEX low-field side

In this contribution, we present a tool for the generation of waves in the drift frequency range.We have demonstrated that electrostatic disturbances can be linearly excited, and detected for different values of the drive frequency and the imposed vertical wave number. The drive frequency is adjusted to match the induced ExB frequency. Direct measurements of the plasma response and of the wave vector k necessary for the identification of the antenna excited mode are obtained using a coherent detection technique. Comparisons of the measured response with the theoretical predictions of the Hasegawa-Wakatani model on the basis of the launched antenna k-spectrum and experimentally measured wave vector are performed. The predicted density response shows agreement for one peak of experimentally measured density response corresponding to a resonant peak that matches a drift mode. The non-resonant peaks, on the other hand, remain unexplained with the current linear model. A linear excitation of drift waves is thus shown in a toroidal plasma using a tunable antenna positioned in the region of maximum density gradient. Finally, in this paper, we have ignored potential wave-wave nonlinear coupling. Such analysis will be subject of future investigations.