Shock Acceleration Within 1 to 36 AU During a Five Year Interval Centered on the 1986 Solar Minimum

We have used intensities of low energy ions from the LECP instrument on the interplanetary probes Voyagers 1 and 2 (E >= 30 keV) and on the earth-orbiting satellite IMP-8 (E >= 300 keV) to examine the variation of shock-accelerated ions during the 5 year interval centered on the solar minimum of September 1986. In early 1985 there was a 50-fold decrease in the flux of ~ 1 MeV ions, observed first at 1 AU, and then ~ 50 days later at Voyager 2 (at 16 AU).