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Momentum and Pressure Balance of a Comet Ionosphere

Nilsson, H.; Goetz, C.; Richter, I. +3 more

We calculate the momentum flux and pressure of ions measured by the Ion Composition Analyzer (ICA) on the Rosetta mission at comet 67P/Churyumov-Gerasimenko. The total momentum flux stays roughly constant over the mission, but the contributions of different ion populations change depending on heliocentric distance. The magnetic pressure, calculate…

Singing Comet Waves in a Solar Wind Convective Electric Field Frame

Goetz, C.; Taylor, M. G. G. T.; Plaschke, F.

The cometary plasma environment at low gas production rates is dominated by highly compressional, large-amplitude magnetic field waves in the 10-100 mHz range. They are thought to be caused by an ion-Weibel instability due to a cross-field current, which is caused by the cometary ions that are accelerated along the solar wind convective electric f…

Simultaneous Observation of Negatively and Positively Charged Nanograins at Comet 67P/Churyumov-Gerasimenko

Goldstein, R.; Goetz, Charlotte; LLera, K. +1 more

Observations near comet 67P by Rosetta show evidence of charged nanograins. Specifically, the ion and electron sensor (IES) observed negative particles with energy/charge (E/q) consistent with charged nanograins. However, theory predicts that both polarities should be present. On 19 September 2014, IES detected positively and negatively charged pa…