Solar Maximum Predictions of the Location of the Solar Wind Termination Shock from Observations of Anomalous Cosmic Rays in the Outer Heliosphere
E. C. Stone and A. C. Cummings
Space Radiation Laboratory,
Caltech, Pasadena, CA 91125, USA

The inclination or ``tilt'' of the heliospheric current sheet (HCS) has been steadily increasing over the past few years and has now reached values above 70 degrees. At such high values, drifts in the large-scale interplanetary magnetic field should be interrupted and diffusion should be the dominant transport mechanism. The solar wind carries the magnetic field into the outer heliosphere, and it appears from the time history of the tilt of the HCS that by the end of 1999 transport in the region between the Voyager spacecraft and the termination shock should be dominated by diffusion. If so, observations of the intensity gradients of anomalous cosmic rays (ACRs) between the two Voyager spacecraft and observations of the shapes of the ACR energy spectra permit an estimate of the location of the solar wind termination shock. We will examine the latest Voyager data to see what inferences can be made. This work was supported by NASA under contract NAS7-918.