Turbulent particle transport in Tore Supra

Full text: Anomalous particle pinch has been unambiguously identified in Tore Supra. Density profile remains peaked, in absence of the Ware pinch, over a time up to 6min30s. This anomalous particle pinch is predicted by turbulence theories. Here, the parametric dependence of the anomalous pinch is studied in order to discriminate among the two main theoretical predictions. One predicts a dependence to the temperature gradient, the other to the magnetic field curvature. The main finding of this work is that the inward pinch driven by the magnetic field gradient is dominant. Nevertheless, in the plasma core (r/a < 0.3), the direction of the pinch is sensitive to the temperature gradient. The results are consistent with micro-stability analyses, which indicate that TEM turbulence is dominant in the gradient region (0.3 < r/a < 0.6), while ITG turbulence takes place in the core. (author)