Maximum dust density (solid lines) and gas density (dotted lines) fluctuations as a function of time for different values of the dust grain size s_d, longitudinal Mach number (perpendicular one being varied too) ${\mathcal{M}}_{\parallel }$, gas initial density n_H, and plasma parameter β. The dust density mean value for pure hydrodynamics simulations is displayed for reference as dashed lines. When not varied, β=0.7.