Preferred frequency of Ion Acoustic Waves in a low temperature bounded plasma

The effect of a preferred frequency of lon Acoustic Waves (IAW) which tone burst excited IAWs exhibits a fixed amplitude, is an interesting phenomenon. The existence of a preferred frequency is most evident when tone-burst IAWs were launched into a quiescent plasma where the propagating wave-package exhibits the preferred frequency regardless of the excitation waveform. This phenomenon has been scatteredly observed in student laboratories and often seen in experiments using tone burst excited IAWs, but poorly recorded and studied. This talk presents a systematic, experimental study of such phenomena in a quiescent multi-dipole confined hot cathode discharge with varying electron temperature, plasma density, neutral pressure, excitation waveform, and sheath thickness of the excitation grid associated with the excitation amplitude. These parameters affect the dispersion relation, damping condition, and the available Fourier components of the IAWs and are expected to reveal the underlying mechanism determining the preferred frequency of IAW propagation in a bounded plasma. Excited, continuous wave IAWs are also studied to investigate whether this phenomena is also common to a possible existence of a low frequency resonance IAW frequency in a low temperature bounded plasma.