Two-fluid model of the plasma flow in the magnetar magnetosphere. Panels (a) and (b) show the Lorentz factors of positrons, γ₊, and electrons, γ₋. In this example, we have assumed that the e^± outflow is injected at r = 2R_⋆ with a fixed multiplicity ﹩{ \mathcal M }=100﹩ (which remains constant along the outflow). The particles move along the magnetic field lines (thick dashed green and white lines) and resonantly scatter thermal photons streaming from the surface of the magnetar. Radiation exerts a drag force on both electrons and positrons. Its local strength is characterized by the value of D_± calculated in the model; the contours of D_± = 1, 10, and 100 are indicated by the red curves. In panel (c), we show γ_± as well as γ_⋆ along the thick dashed green field line, which has ﹩{R}_{{\rm{\max }}}=900{R}_{* }﹩. The evolution of γ_±, when only the radiative force is considered, is shown with dashed lines. We also show the velocities of electrons (﹩{v}_{d,-}^{{\prime} }﹩) and positrons (﹩{v}_{d,+}^{{\prime} }﹩) in the RL frame. The orange and blue shaded regions have D₊ ≥ 3 and D₋ ≥ 3, respectively.