The Sweeping Langmuir Probe on board the PICASSO CubeSat was designed to measure plasma parameters. Before launch, the instrument was tested in a plasma chamber. It is shown that the traditional method to interpret the data cannot be applied directly for this type of probe, and an adaptation is proposed. It is reported how, with a reduced number of data points, the plasma parameters can still be retrieved. Finally, the effects of the contamination of the probe surface are discussed.

The solar wind magnetic field drapes around the active nucleus of comet 67P/CG, creating a magnetosphere. The solar wind density increases and with that the pressure, which compresses the magnetosphere, increasing the magnetic field strength near Rosetta. The higher solar wind density also creates more ionization through collisions with the gas from the comet. The new ions are picked-up by the magnetic field and generate mirror-mode waves, creating low-field high-density "bottles" near 67P/CG.

We present a first report on magnetic field measurements made in the coma of comet 67P/C-G in its low-activity state. The plasma environment is dominated by quasi-coherent, large-amplitude, compressional magnetic field oscillations around 40mHz, differing from the observations at strongly active comets where waves at the cometary ion gyro-frequencies are the main feature. We propose a cross-field current instability associated with the newborn cometary ions as a possible source mechanism.