The possibility of Langmuir wave generation in electronpositron plasma is considered. As a result of induced scattering, these waves find themselves in the superluminal region. Thereby such waves can transfer energy to the Crab Nebula essentially without loss, where the remaining plasma creates condition of collapse of Langmuir waves. As a result, the tail of the e± distribution function stretchs out to Lorentz factors of the order of γ± ≤ 109. Via synchrotron emission, particles of these energies can radiate X and γ - radiation.