Possible observation of charged nanodust from comet 67P/Churyumov-Gerasimenko: An analysis for the ROSETTA mission

In this study we investigate whether this is a realistic option. We show that when the comet activity is low between 3.25 and 2.7 AU, the cometary surface and a part of the dust particles get charged due to the charging currents of the solar wind and photoionization as a result of solar radiation. The nucleus׳ surface potential depends on the solar wind density, and it is higher than +4 V for solar zenith angle between 0° and 50° for solar wind density n(d=1 AU)=4×10−6 m−3, and nano-size dust gets immediately accelerated when it collected Q=+1e positive charge due to photoelectron emission. The energy of this charged nanodust is higher than 4 eV and it could be detected not far from the subsolar region by the ion and electron sensor (IES) of the Rosetta Plasma Package. In this paper we examine this process in detail.