One can see the impact of the ion current on the electric potential and also on the measurements of the electron spectrometer PEACE in the following figures. Without an ion current, the spacecraft potential is between 17 and 20 Volts. This reduces to 6 to 7 Volts at 12 µA and further to 3 Volts at 37 µA.

The spectrograms show the count rates of the electron spectrometer PEACE in equal time span at an energy range of approximately zero to to approximately 10 electron volts. The three images show measurements in different directions (parallel to the spin axis, in the spin plane and anti-parallel to the spin axis). The interfering photo electrons disappear almost completely at the strongest ion current.