Small scale turbulence and anomalous electron heat flux in the TFR tokamak

Electron density fluctuations are measured by microwave scattering. The frequency spectrum ( omega / omega *<3) and the transverse wave vector spectrum (k perpendicular to rho i <or approximately=1) are compatible with electrostatic drift modes. Azimuthal dependence of the fluctuations is found to be negligible in a regime where nu * approximately 1. The turbulence and heat transport are found to be reduced when the electron density is increased above 10 14 cm -3 . Anomalous heat transport is calculated, assuming trapped electron drift modes and compared to the electron thermal balance. A rough agreement is found in a small region (r/a approximately 05), if it is assumed that the unstable modes are strongly localized on magnetic rational surfaces, but the radial profiles found are not compatible.