Profiles of ion density, magnetic field B_z, and electric fields E_x and E_y at times 1 ns (a) and 1.5 ns (b) after the beginning of the simulation. At 1 ns (≈12 ns for the experiment), the two fast shocks propagate without perturbing each other, as their profiles correspond to the one of the single shock case. At 1.5 ns (≈12.5 ns for the experiment), the interaction between the two shocks makes the ion density and the magnetic field B_z increase and pile up in the middle; the electric field E_x presents several spikes also due to the interaction between the downstream fast magnetosonic waves; the inductive E_y does not drastically change structure or magnitude, but it presents opposite signs in the downstream regions depending on the propagation direction of the shock. We point out that the profiles relative to the single shock are shifted of Δx = −L_x/12 in order to simplify the comparison.