The European Space Agency’s spacecraft ROSETTA has reached its final destination,
comet 67P/Churyumov-Gerasimenko. Whilst orbiting in the close vicinity of the nucleus the
ROSETTA magnetometers detected a new type of low-frequency waves possibly generated by a
cross-field current instability due to freshly ionized cometary water group particles. During separation, descent and landing of the lander PHILAE on comet 67P/Churyumov-Gerasimenko, we
used the unique opportunity to perform combined measurements with the magnetometers onboard
ROSETTA (RPCMAG) and its lander PHILAE (ROMAP). New details about the spatial distribution
of wave properties along the connection line of the ROSETTA orbiter and the lander PHILAE
are revealed. An estimation of the observed amplitude, phase and wavelength distribution will be presented as well as the measured dispersion relation, characterizing the new type of low-frequency
waves. The propagation direction and polarization features will be discussed using the results of a
minimum variance analysis. Thoughts about the size of the wave source will complete our study