Initial measurements of edge plasma turbulence on ATF

Summary form only given. Initial measurements of the electrostatic turbulence on the edge of the ATF torsatron are carried out in order to study their effect on the particle transport in this currentless magnetic configuration. Spatial profiles of the plasma electron density n_e, temperature T_e, and fluctuations in density (n˜_e) and in the plasma potential (φ˜) are measured around the last closed flux surface (LCFs) using a fast reciprocating Langmuir probe. Measurements made on electron cyclotron heated (ECH) plasmas indicate that at the LCFS T_e~20-40 eV and n_e~10¹² cm^-3 for a line-average electron density of (3-5)×10¹² cm^-3 at 1 T operation. The fluctuations depart increasingly from the Boltzman relation eφ˜/T_e=n˜_e /n_e as the probe is moved into plasma where T_e>20 eV, with n˜_e/n _e~5%, eφ˜/T_e~2n˜_e /n_e about 2 cm inside the LCFS. The radial variation of the DC radial electric field results in a velocity shear layer whose position is independent of the limiter location. The particle flux estimated from the global particle balance is comparable with the fluctuation-driven particle flux