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Solar wind interaction with comet 67P: impacts of corotating interaction regions
Journal article   Open access   Peer reviewed

Solar wind interaction with comet 67P: impacts of corotating interaction regions

Niklas J. T Edberg, A. I Eriksson, E Odelstad, E Vigren, D. J Andrews, F Johansson, J. L Burch, C. M Carr, E Cupido, K. -H Glassmeier, …
Journal of geophysical research. Space physics, Vol.121(2), pp.949-965
09/14/2018
DOI: 10.1002/2015JA022147
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https://doi.org/10.1002/2015JA022147View
Published (Version of record) Open Access

Abstract

Solar wind interaction with comet 67P: Impacts of corotating interaction regions, J. Geophys. Res. Space Physics, 121, 949-965, 2016 We present observations from the Rosetta Plasma Consortium of the effects of stormy solar wind on comet 67P/Churyumov-Gerasimenko. Four corotating interaction regions (CIRs), where the first event has possibly merged with a CME, are traced from Earth via Mars (using Mars Express and MAVEN) and to comet 67P from October to December 2014. When the comet is 3.1-2.7 AU from the Sun and the neutral outgassing rate $\sim10^{25}-10^{26}$ s$^{-1}$ the CIRs significantly influence the cometary plasma environment at altitudes down to 10-30 km. The ionospheric low-energy \textcolor{black}{($\sim$5 eV) plasma density increases significantly in all events, by a factor $>2$ in events 1-2 but less in events 3-4. The spacecraft potential drops below -20V upon impact when the flux of electrons increases}. The increased density is \textcolor{black}{likely} caused by compression of the plasma environment, increased particle impact ionisation, and possibly charge exchange processes and acceleration of mass loaded plasma back to the comet ionosphere. During all events, the fluxes of suprathermal ($\sim$10-100 eV) electrons increase significantly, suggesting that the heating mechanism of these electrons is coupled to the solar wind energy input. At impact the magnetic field strength in the coma increases by a factor of ~2-5 as more interplanetary magnetic field piles up around of the comet. During two CIR impact events, we observe possible plasma boundaries forming, or moving past Rosetta, as the strong solar wind compresses the cometary plasma environment. \textcolor{black}{We also discuss the possibility of seeing some signatures of the ionospheric response to tail disconnection events
Physics - Space Physics

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