AUTORESONANCE SOLITON IN A PLASMA

Powerful electromagnetic pulses propagating in a plasma along a strong magnetic field under cyclotron-resonance conditions am shown to take the form of solitons with ''built-in'' Langmuir oscillations. Nonlinea r saturation of the field amplitude arises as a result of charge separ ation in a plasma due to the electromagnetic radiation pressure. A dis crete set of carrier frequencies for soliton envelope solutions is det ermined by the ratio of the frequency of nonlinear longitudinal electr on oscillations in a field of an electromagnetic wave to the plasma La ngmuir frequency. With plasma density decrease, the discrete frequency spectrum is shown,by numerical integration, to become a continuous on e. An asymptotic analytical solution is obtained, in this case, descri bing the physics of electromagnetic radiation interaction with electro ns and ions of a plasma under strong nonlinearity conditions.