Panel a shows the growth of the primary fluid instabilities at t = 54 s, in terms of ¹²C mass fraction and in logarithmic scale, for model 1.0 M_⊙ CO white dwarf. The other panels show snapshots of the convective front when it is at a distance of 4 pressure scale heights above the CEI for models 0.8 M_⊙ CO (panel b), 1.0 M_⊙ CO (panel c), 1.15 M_⊙ CO (panel d), 1.15 M_⊙ ONe (panel e), and 1.25 M_⊙ ONe (panel f). The snapshots are shown in terms of ¹²C mass fraction for CO-rich substrates, and in terms of ²⁰Ne mass fraction for ONe-rich substrates, both in logarithmic scale. The times are t = 326s, t = 149s, t = 66s, t = 194s, and t = 133s, respectively. The reflection condition is imposed in the lower boundary, which is located 50 km below the CEI for all the simulations. See movies available online.