Numerical simulation of Rosetta Langmuir Probe

Abstract: By modelling and simulating the ESA spacecraft Rosetta in a plasma with solar wind parameters, and simultaneously simulating a particle detection experiment of Langmuir probe voltage sweep type using the ESA open source software SPIS Science, we investigate the features of Rosetta’s envi- ronment in the solar wind and the e↵ect of photoemission from the space- craft on the measurements made by the Langmuir Probe instrument on board Rosetta. For a 10 V positively charged spacecraft and Maxwellian distributed photoelectron emission with photoelectron temperature, Tf = 2 eV in a plasma of typical 1 AU solar wind parameters: ne = 5 ⇥ 106 m3, vSW = 4 ⇥ 105 m/s, Te = 12 eV, Tion = 5 eV, we detect a floating potential of 6.4 (± 0.2) V at Langmuir probe 1. Two models used in literature on photoemission was used and compared and we report a clear preference to the Maxwellian energy distribution of photoelectrons from a point source model with our simulation result.