Particle acceleration by a fast ordinary mode in an electron-positron plasma

The possibility of nonresonant particle acceleration in an electron-positro n plasma of a pulsar magnetosphere is investigated. A mechanism is proposed in which modulations of a fast superluminal (with phase velocity exceeding the speed of light) longitudinal ordinary mode (caused by a beat wave of t wo transverse electromagnetic waves propagating along the magnetic field) s timulate nonresonant quasilinear diffusion leading to a redistribution of p lasma particles in pitch angle. The resulting perpendicular momenta of the particles lead to synchrotron radiation which is in the gamma-ray range. (C ) 2000 American Institute of Physics. [S1070-664X(00)01304-5].