WAKE-FIELD EXCITATION IN PLASMA BY A RELATIVISTIC ELECTRON PULSE WITHA CONTROLLED NUMBER OF SHORT BUNCHES

The excitation of wake fields in plasma by a train of relativistic ele ctron bunches was studied both theoretically and experimentally. It fo llows from the theoretical analysis that the amplitude and spatial str ucture of the electric field of wake waves excited by either a high pa rticle density single pulse or by a train of relatively low particle d ensity bunches should be approximately equal if the total charge in bo th cases remains the sane. It was shown experimentally that a very hig h electric field is excited in plasma by a train of short relativistic bunches if the bunch repetition rate coincides with the electron Lang muir frequency.