Mars is prone to atmospheric turbulence. Its thin, nearly cloudless atmosphere and low surface thermal inertia entail strong near-surface unstable temperature gradients, resulting in convective turbulencecells, plumes, vortices-at daytime in the planetary boundary layer (PBL;Larsen et al., 2002;Petrosyan et al., 2011;Tillman et al., 1994). This induces a wealth of daytime high-frequency variations in the atmospheric pressure, wind and temperature measured by landers and rovers (Martínez et al., 2017 for a review). Conversely, nighttime conditions in Mars' PBL are highly stable because of strong radiative cooling efficiently inhibiting convection. Nevertheless, in the night, shear-driven weak turbulence may exist on Mars (e.g., Pla-García et al., 2020;Savijärvi, 1999) and, intriguingly, vortex-induced pressure drops have been observed in Gale Crater by Curiosity (Ordonez-Etxeberria et al., 2018.

In this work, we present the results of simulations carried out for N2-H2 capacitively coupled radio-frequency discharges, running at low pressure (0.3-0.9 mbar), low power (5-20 W), and for amounts of H2 up to 5%. Simulations are performed using a hybrid code that couples a two-dimensional time-dependent fluid module, describing the dynamics of the charged particles in the discharge, to a zero-dimensional kinetic module, that solves the Boltzmann equation and describes the production and destruction of neutral species. The model accounts for the production of several vibrationally and electronic excited states, and contains a detailed surface chemistry that includes recombination processes and the production of NHx molecules. The results obtained highlight the relevance of the interactions between plasma and surface, given the role of the secondary electron emission in the electrical parameters of the discharge and the critical importance of the surface production of ammonia to the neutral and ionic chemistry of the discharge.