Excitation of Electron Plasma Oscillation by Ion-Acoustic Waves

Electron plasma oscillations were generated by application of one characteristic low frequency fields to a mesh anode. Conditions for the excitation of electron plasma oscillations are that the positive column is bounded by the ion-sheath and the voltage of the applied signal is above a certain value. These excited oscillations, which are of the Looney-Brown type, are possible only on a certain phase of the low frequency fields. The low frequencies associated with the excitation coincide with those of radial ion-acoustic wave modes. Therefore only the external frequency which satisfies the boundary condition determined by the argument of the Bessel function can participate in the excitation of electron plasma oscillation.