On the velocity distributions of dust‐related inner‐source pickup ions

Abstract

We simulate velocity distributions for inner‐source pickup ions in two scenarios for their origin. One scenario creates inner‐source pickup ions by charge exchange and energy loss in very small (typically submicron‐sized) dust grains (Wimmer‐Schweingruber and Bochsler 2003), while the other liberates solar wind ions previously implanted in larger (typically 1 μm) dust grains (Geiss et al. 1995; and Gloeckler and Geiss 1998). The two scenarios differ by the initial velocity with which the pickup ions are created; the fine‐dust model produces a wide initial velocity distribution, while the coarse‐dust model releases them essentially at rest. We investigate the differences in the distributions once these ions have been transported out to an observer at 1 AU or beyond.