Dispersion relation of high frequency waves in a beam-plasma system

The dispersion relation of electron plasma waves in a beam-plasma system has been investigated experimentally and compared with numerical calculations using different radial density distribution functions in an attempt to use these waves for accurate determination of the electron density. It is found that calculations using the linear dispersion relation gives a good fit to the experimental data although test waves are launched in the presence of large amplitude waves excited by the beam-plasma system. However, the existence of a multiple peaked frequency spectrum is reflected in the dispersion relation as a steplike distortion.