A study of microscopic fluctuations of density ñ and potential in the scrape-off layer has been performed. The frequency spectra of and show a strongly turbulent character, as observed in many tokamaks. The fluctuation levels of /n and e/kTe are consistent with predictions based on non-linear collisional drift wave models. The line average density and heating power dependences of /n and e/kTe are studied in two types of currentless plasma, namely electron cyclotron resonance heating plasmas and neutral beam injection heating plasmas. Their parametric dependences are compared with the trends of the energy confinement time. Finite beta effects on ef/kTe and /n are also discussed.