COSMIC-RAY MODULATION IN THE 3-D HELIOSPHERE

The basic physical processes that lead to the long-term modulation of cosmic rays by the solar wind have been known for many years. However our knowledge of the structure of the heliosphere, which determines wh ich processes are most important for the modulation, and of the variat ion of this structure with time and solar activity level is still inco mplete. Study of the modulation provides a tool for probing the scale and structure of the heliosphere. While the Pioneer and Voyager spacec raft are surveying the radial structure and extent of the heliosphere at modest heliographic latitudes, the Ulysses mission is the first to undertake a nearly complete scan of the latitudinal structure of the m odulated cosmic ray intensity in the inner heliosphere (R<5.4 AU). Uly sses will reach latitudes of similar to 80 degrees S in September 1994 and similar to 80 degrees N in July 1995 during the approach to minim um activity in the 11 year solar cycle. We present a first report of m easurements extending to latitudes of similar to 52 degrees S, which s how surprisingly Little latitudinal effect in the modulated intensitie s and suggest that at this time modulation in the inner heliosphere ma y be much more spherically symmetric than had generally been believed based upon models and previous observations.