Structure and Dynamics of the Interaction Region at Comet 67P/Churyumov-Gerasimenko: Comparing Numerical Simulations and RPC Magnetic Field Observations

The arrival of the Rosetta spacecraft at its target comet 67P/Churyumov-Gerasimenko in August 2014 is the onset of the main mission phase, the escort of the comet on its journey around the Sun. Among the instruments deployed on the spacecraft a triaxial fluxgate magnetometer can be found. This instrument is part of the Rosetta Plasma Consortium and allows us to study the magnetic properties of the plasma interaction at the comet. This interaction will be weak in the first months after the arrival because the expected gas production rate is several magnitudes lower than active comets close to their perihelion. In this paper we will present some of the magnetic field measurements in this unique environment and compare them with the latest hybrid plasma simulations, which predict the presence of a Mach cone, a deflection of the solar wind depending on the orientation of the interplanetary magnetic field, and the presence of waves for the early escort phase of the mission.