Scheme of the considered emission region in the open magnetic field lines of a neutron star magnetosphere. The emission region (plasma frame) moves in the pulsar frame with a Lorentz factor γ_s along the magnetic field line. In our approach, we considered the electric current density j′(x′, t′) as a function of space and time. The plasma frame is denoted by primes everywhere except in Appendices A and B. In the plasma frame, the emission region has a cylindrical shape with a length L′ along the axis x′∥B and a diameter D′≪L′. The length L′ depends on simulation parameters (see text), but we have fixed the diameter to notional D′ = 1.13 m to calculate the emission power. In the pulsar reference frame, the radio emission occurs at a wave vector k = k ⋅ n = ω/c ⋅ n at an angle θ to the magnetic field.