Cometosheath observations around comet 67P/Churyumov-Gerasimenko

The Rosetta spacecraft orbited the comet 67P/Churuymov-Gerasimenko for approximately two years, primarily remaining close to the nucleus, unlike previous cometary flyby missions. The combination of Rosetta's close orbit and comet 67P's relatively low cometary activity make detections of the bow shock difficult. However, magnetosheath-like proton distributions have been observed, indicating Rosetta indeed was downstream of a bow shock, during periods of higher cometary activity. Here, we search the Ion Composition Analyzer (ICA) data for additional evidence of the cometosheath, the region downstream of the bow shock analogous to a magnetosheath. We examine the proton velocity distributions for high time and spatial variability that is not correlated with changes in the electric or magnetic fields. We present an overview of cometosheath detections and a discussion of the relation between the cometosheath and bow shock properties. Other work shows that the electric potential of the solar wind can be retrieved from the differential slowing of the solar wind species, so we compare time periods with a high electric potential to cometosheath detections, as a high potential can also indicate shock formation.