Pioneer 8 plasma-wave measurements at distant bow-shock crossings.

Evaluation of enhanced low-frequency plasma-wave levels detected near the Pioneer 8 multiple bow-shock crossings encountered beyond 120 earth radii (Bavassano et al., 1971) and of high-frequency plasma waves detected in the upstream region. It is suggested that the distant interaction of the solar wind and the magnetosheath produced nonthermal electrons of the type commonly found upstream from the subsolar shock. The bow-shock position is compared with fluid model predictions, and some distinctions between the standing bow shock and the propagating interplanetary shock are considered.