[Heber 1995 a]

Nucleon modulation from the Ulysses Rapid Latitude Scan:
COSPIN/KET Results

B. Heber, A. Raviart, C. Paizis, M. S. Potgieter, W. Dröge, R. Ducros, P. Ferrando, L. J. Haasbroek, H. Kunow, R. Müller-Mellin, C. Rastoin, K. Röhrs, H. Sierks, and G. Wibberenz.
Nucleon modulation from the Ulysses Rapid Latitude Scan: COSPIN/KET Results.
Proceedings of the 24th International Cosmic Ray Conference 4, 764-767. 1995

Contents

Observations of cosmic rays in high latitudes can be used for the improvement of "standard" modulation theories of the cosmic rays in the heliosphere. The authors compare measurements of galactic nuclei made by the Kiel Electron Telescope on board the Ulysses spacecraft with results from a "standard" steady state 2D drift model.

During the fast decline from the south polar passage in September 1994 to the crossing of the ecliptic plane in March 1995 solar activity was relatively low and temporal variation very small. For the different energy channels the authors normalized the count rates at heliographic latitude theta to the mean values when Ulysses was between theta = -5° and theta = 5°. These normalized count rates for particles with rigidity over 0.8 GV/c over the southern solar pole are up to a factor of 5 smaller than the predicted ones. Also significant latitudinal effects are only observed when Ulysses is above 30° heliographic latitude. To separate spatial from temporal variations, measurements from the Chicago particle instrument on board IMP-8 and from the Climax Neutron Monitor are used.

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