LATITUDINAL DISTRIBUTION OF GREATER-THAN-106 MEV PROTONS AND ITS RELATION TO THE AMBIENT SOLAR-WIND IN THE INNER SOUTHERN AND NORTHERN HELIOSPHERE - ULYSSES COSMIC AND SOLAR PARTICLE INVESTIGATION KIEL ELECTRON TELESCOPE RESULTS

We present observations and model calculations of the modulated intens ities of galactic cosmic ray protons above 106 MeV/n along the Ulysses trajectory. Data are taken by the Cosmic and Solar Particle Investiga tion (COSPIN) Kiel Electron Telescope (KET) from spring 1993 to fall 1 996. During this time period solar activity decreased and galactic cos mic rays recovered, To separate spatial from temporal variations we us ed the University of Chicago measurements from IMP 8 near Earth and co mpare the residual spatial variation with time independent modulation models. According to standard drift dominated modulation model, one wo uld expect a radial gradient of approximate to 2%/AU and a latitudinal gradient of approximate to 1.2%/degree in both hemispheres. The measu red mean radial gradient of approximate to 3%/AU is within the uncerta inties in good agreement with the model predictions, However, the meas ured mean latitudinal gradient has a value of (0.33 +/- 0.04)%/degree in both hemispheres at intermediate latitudes and is by a factor of 4 lower than expected, In the modified models the latitudinal gradient i s in agreement with the measured ones when we increase the diffusion c oefficient Mss perpendicular to the magnetic field in polar direction to a value of 15% of the diffusion coefficient parallel to the magneti c field, The latitudinal gradients >106 MeV protons calculated by modi fied modulation models are in very good agreement with the measured on es at intermediate latitudes, At lower latitudes, when Ulysses is embe dded in the streamer belt, the models predict approximately the same l atitudinal gradient than at intermediate latitudes, whereas the measur ed ones are significant smaller, or even vanishing, The observations s upport the previous conclusion from Paizis et al. [1995] that a signif icant latitudinal gradient is only observed when Ulysses is outside th e streamer belt, Another remarkable observation is the difference of t he radial gradient G(r) at similar to 3.5 AU in the southern (G(r) app roximate to 3.5%/AU) and in the northern hemisphere (G(r) approximate to 2.3%/AU), Probable reasons for the significantly lower radial gradi ent in the northern hemisphere can be either a spatial asymmetry of th e heliosphere or temporal variations.