Overmodulation of an upper hybrid electromagnetic beam in a plasma
Article first published online: 7 DEC 2012
Copyright 1981 by the American Geophysical Union.
Volume 16, Issue 3, pages 409–415, May-June 1981
How to Cite
1981), Overmodulation of an upper hybrid electromagnetic beam in a plasma, Radio Sci., 16(3), 409–415, doi:10.1029/RS016i003p00409., and (
- Issue published online: 7 DEC 2012
- Article first published online: 7 DEC 2012
- Manuscript Accepted: 27 DEC 1979
- Manuscript Received: 26 FEB 1979
Using the fluid equations for the nonlinear response of electrons, we have studied the self distortion of an amplitude-modulated upper hybrid laser beam and a Gaussian laser pulse in a collisionless magnetoplasma. The beam possesses a Gaussian distribution of intensity in the transverse plane and gives rise to a ponderomotive force on the electrons. The parallel component of ponderomotive force causes a redistribution of electron density, which gets modulated at the modulation frequency of the beam, the profile of modified electron density results in the selffocusing of the beam. The high- and low-amplitude portions of the beam are focused to different extents, and a severe distortion in the amplitude envelope of the beam results. For a typical 10.6-μ, CO2 laser of 108 W the change in the index of modulation becomes ∼100% after propagating a distance ∼0.4 cm. Similarly, the intensity envelope of a Gaussian laser pulse also gets severely distorted as it propagates in the plasma.