ION ENERGY EQUATION FOR THE HIGH-SPEED SOLAR-WIND - ULYSSES OBSERVATIONS

Ulysses data in the high-speed solar wind that cover a wide range of l atitudes centered on the solar poles were studied to test whether a po lytrope law can be used to close the ion energy equation. Three approa ches were taken, We determined the correlation between proton temperat ure and density (1) in the free expansion of the highspeed solar wind between 1.5 and 4.8 AU, (2) in steepened microstreams at high latitude s, and (3) at the edges of the equatorial band of solar wind variabili ty. Strong correlations were observed in all data subsets that are con sistent with a single polytrope relation, T-p = aN(p)((gamma-1)), whe re our best estimate gamma is between 1.5 and 1.7. The best fitting r elation T-p = (2.0 +/- 0.13) x 10(5) N-p(0.57).