Articles | Volume 31, issue 4
Ann. Geophys., 31, 633–638, 2013
Ann. Geophys., 31, 633–638, 2013

Regular paper 10 Apr 2013

Regular paper | 10 Apr 2013

Coherent amplitude modulation of electron-beam-driven Langmuir waves

K. Baumgärtel K. Baumgärtel
  • Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany

Abstract. A linear approach to the phenomenon of irregular amplitude modulation of beam-driven Langmuir waves, developed in a previous paper, is extended to explain periodic modulation as well. It comes about by beating of the fastest growing mode of the instability with beam-aligned plasma oscillations. They are naturally generated in a uniform domain of beam–plasma interaction prior to the onset of the instability. Particle-in-cell (PIC) simulations support the results of the linear analysis.