Carbon (lower/left group of lines) and oxygen (upper/right group of lines) ignition curves in the ocean of a magnetar with mass M = 1.4   M_⊙, radius 12 km, and magnetic field B = 10¹⁴ G for different angles between the field lines and the normal to the surface: θ_B = 0°, 60°, 75°, and 85° (respectively, 4 solid lines from top to bottom in each of the two groups). For comparison, the ignition curves given by Eq. (A.1) are plotted by the dot-dashed lines, and the ignition curves without accounting for the magnetic field effects are shown by dashed lines.