Cosmic Ray Studies Out of the Ecliptic

Since early 1985, negative latitudinal gradients in the fluxes of anomalous and galactic cosmic rays have been observed by Voyager 1, which is now -28° above the ecliptic. The latitudinal gradients are larger than the radial gradients, indicating that particles are streaming into the heliosphere preferentially at low latitudes during this solar minimum. The sign of the latitudinal gradients appear to have reversed since the last solar minimum, consistent with the presence of gradient and curvature drifts.