Timescales relevant to the acceleration of a silicate dust grain of size a = 10⁻⁶ cm and shock velocity u_sh = 10⁹ cm/s vs. the grain velocity, β, in units of c. The relevant typical times shown are: the acceleration time, τ_acc (solid black), the grain-grain interaction time, τ_g − g (solid thin green), the gyration time (dashed blue), the grain loss time from frictional interactions with the background plasma (dashed red), the associated sputtering time (dash-dotted thin orange), and the thermal sputtering time (dotted thin orange).