Latitudinal dependence of the solar wind fluctuations

We have studied the dependence of the fluctuations associated to magnetic field, proton density, proton temperature and solar wind velocity on the angular displacement from the interplanetary current sheet. We show that, during the minimum of the solar cycle, there exists a narrow latitudinal region extending around the current sheet, where the variability of these parameters, except velocity, increases with decreasing the angular displacement from the current sheet. Moreover, this phenomenon depends on the scale-length we are looking at. In fact, while for sizes less than a few million kilometers latitudinal gradients appear to be negligible, at larger scales the variability of the magnetic field, proton density and temperature clearly increases moving from high to low latitudes. We explain these latitudinal gradients by forming the hypothesis of the existence of interplanetary structures, larger than a few million kilometers, convected by the solar wind and more frequently found close to the current sheet than at high latitudes