Interaction dust–plasma in Titan's ionosphere: Feedbacks on the gas phase composition

Titan's organic aerosols are formed and spend some time in the ionosphere, an atmospheric layer ionized by solar VUV photons and energetic particles coming from the magnetosphere of Saturn, forming a natural N2-CH4-H2 plasma. Previous works showed some chemical evolution processes: VUV photons slightly alter the aerosols nitrile bands, hydrogen atoms tend to hydrogenate their surface and carbon-containing species participate to the growth of the aerosols. This work investigates the effect of the other plasma species, neglected until now, namely the N2-H2 derived ions, radicals and electronic or vibrational excited states. Industrial plasmas often use N2-H2 discharges to form ammonia-based fertilizers, for metal nitriding, and to erode organic surfaces. Consequently, these are likely to affect Titan's organic aerosols.