. The data from all Rosetta Plasma Consortium instruments and from the ROSINA COPS
instrument are used to study the interaction of the solar wind with the outgassing cometary nucleus
of 67P/Churyumov-Gerasimenko. During 6 and 7 June 2015, the interaction was first dominated
by an increase in the solar wind dynamic pressure, caused by a higher solar wind ion density. This
pressure compressed the draped magnetic field around the comet, and the increase in solar wind
electrons enhanced the ionization of the outflow gas through collisional ionization. The new ions
are picked up by the solar wind magnetic field, and create a ring/ring-beam distribution, which, in a
high-β plasma, is unstable for mirror mode wave generation. Two different kinds of mirror modes
are observed: one of small size generated by locally ionized water and one of large size generated
by ionization and pick-up farther away from the comet.