Abstract
Our picture of modulation in the inner heliosphere has been greatly affected by observations from the Ulysses mission, which since 1992 has provided the first comprehensive exploration of modulation as a function of latitude from 80° S to 80° N heliographic latitude. Among the principal findings for the inner heliosphere are: a) the cosmic ray intensity depends only weakly on heliographic latitude; b) for the nuclear components, and especially for the anomalous components, the intensity increases towards the poles, qualitatively consistent with predictions of drift models for the current sign of the solar magnetic dipole; c) no change in the level of modulation was observed across the shear layer separating fast polar from slow equatorial solar wind near 1 AU; d) 26-day recurrent variations in the intensity persist to the highest latitudes, even in the absence of clearly correlated signatures in the solar wind and magnetic field; e) the surface of symmetry of the modulation in 1994-95 was offset about 10° south of the heliographic equator; f) the intensity of electrons and of low energy (< ∼ 100 MeV) protons showed essentially no dependence on heliographic latitude.
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McKibben, R. Three-dimensional Solar Modulation of Cosmic Ray and Anomalous Components in the Inner Heliosphere. Space Science Reviews 83, 21–32 (1998). https://doi.org/10.1023/A:1005044707585
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DOI: https://doi.org/10.1023/A:1005044707585