The Solar Wind : Probing the Heliosphere with Multiple Spacecraft

The combination of the Voyager spacecraft in the outer heliosphere, Ulysses at high latitudes, and multiple solar wind monitors near Earth provides a unique opportunity to study the global structure and evolution of the solar wind. From solar minimum to solar maximum the latitudinal gradients of density and speed reverse so that at solar maximum speeds are higher near the solar equator, but solar cycle changes in the dynamic pressure occur at all solar latitudes. The MIR frequency increases during the ascending phase of the solar cycle and e ects the cosmic ray intensities. One example shows a MIR that is clearly driven by CMEs. Ulysses and Voyager observations are combined to quantify the speed decrease in the solar wind with distance and estimate the density of the local interstellar medium.