LONGITUDINAL GRADIENTS OF THE DISTRIBUTION OF ANOMALOUS COSMIC-RAYS IN THE OUTER HELIOSPHERE

Recent results, both from observation and theory, suggest that the ter mination shock of the solar wind is not spherical. First, observations made with the Ulysses spacecraft have confirmed that the solar wind m omentum flux increases with latitude, implying an elongation of the sh ock above the sun's poles. Second, results of modeling the global stru cture of the heliosphere indicate that a so-called upwind-downwind asy mmetry of the shock is probable. In view of these findings as well as the observed upwind-downwind asymmetry in pick-up ion fluxes, one migh t suspect the existence of longitudinal gradients in the distributions of anomalous cosmic rays, which are supposedly identical with the pic k-up ions accelerated at the termination shock. We demonstrate that su ch longitudinal gradients should indeed be expected in the outer helio sphere and estimate their magnitude using a three-dimensional modulati on model.