Dark solitons in electron-positron plasmas

We demonstrate that a dark soliton is a stable nonlinear coherent mode in electron-positron plasmas. The dark soliton comprises the minimum of the electromagnetic energy density and the minimum of the plasma density. Contrary to a bright soliton, the dark soliton can advect the trapped charged particles. The energy of trapped particles is well above the kinetic energy of the particles in the background plasma.