Detailed measurements of density and floating potential in the poloidal cross section of a toroidal plasma with an extended source at the minor axis are presented in the first half of the paper. The second part deals with the effect of k/sub /// on curvature-induced low frequency (< omega i, the ion gyro frequency) fluctuations, where k/sub /// is the wavenumber parallel to the ambient magnetic field. The variation in k/sub /// is introduced with the help of a weak vertical magnetic field, which helps in varying the length of the toroidal magnetic field lines. We report a reduction in the fluctuation level in the presence of a weak vertical field.