Since 2014, the European mission Rosetta has been escorting comet 67P/Churyumov-Gerasimenko on its orbit around the Sun. It witnessed the formation of the comet's coma, ionosphere and magnetosphere in the autumn 2014 and has gathered unprecedented information on the existence of plasma boundaries and their subsequent evolution from near-apohelion conditions to the perihelion outburst of activity in September 2015, with mass-loading mechanisms and photochemical processes playing a major role. In these stages, different populations are seen such as solar wind ions (H+, He++), cometary ions (water-group ions) picked up by the solar wind and accelerated to higher energies and highly charged dust. As with previous cometary missions, the mission's extension until September 2016 will be a stepping stone for the constitution of a large and unique dataset, which will foster research topics for decades to come.
On Rosetta, the Rosetta Plasma Consortium (RPC) includes a suite of five scientific instruments monitoring the plasma environment of the comet (e-m fields, electrons and ions). One of them, the dual Langmuir probe instrument (RPC-LAP), measures the electron density and temperature as well as the plasma velocity. The Department of Physics at the University of Oslo is co-Investigator of RPC-LAP and has thus full data access in collaboration with IRF-Uppsala.