STREAM INTERFACES AND ENERGETIC IONS .2. ULYSSES TEST OF PIONEER RESULTS

Ulysses measurements of energetic and solar wind particles taken near 5 AU between 20 and 30 degrees south latitude during a well-developed recurring corotating interaction region (CIR) show that the CIR's coro tating energetic ion population (CEIP) associated with the trailing re verse shock starts within the CIR at the stream interface. This is con sistent with an earlier result obtained by Pioneers 10 and 11 in the e cliptic plane between 4 and 6 AU. The Ulysses/Pioneer finding ns notew orthy since the stream interface is not magnetically connected to the reverse shock, but lies 12-17 corotation hours from it. Thus, the find ing seems to be inconsistent with the basic model that generates CEIP particles at the reverse shock and propagates them along field lines. Eliminating the inconsistency probably entails an extension of the sta ndard model such as cross-field diffusion or a non-shock energization process operating near the stream interface closer to the sun.