Spatially growing dust acoustic waves: experiment and theory

Summary form only given. A dusty plasma is a modification of the usual plasma environment. Here, the usual collection of ions, electrons, and neutral particles is modified by the presence of charged, often micron-sized, particles; i.e., the "dust". These charged microparticles are often highly charged objects in laboratory or industrial plasmas and can cause a significant perturbation to the surrounding plasma environment. In a dusty plasma, one of the most fundamental modes of microparticle oscillation is the dust acoustic wave. This wave is generally modeled as a linear, compressional mode of the charged microparticle component of the plasma. Although first experimentally identified in the mid-1990\´s this wave mode continues to be a subject of intense study because of the possibility of identifying nonlinear phenomena. This presentation discusses a new experimental and theoretical investigation of the dust acoustic wave. In this study, dust acoustic waves in an argon DC glow discharge plasma are investigated using stereoscopic particle image velocimetry techniques. Evidence of the spatial growth of waves over 5 to 7 wavelengths will be presented. The experimental data is compared against an updated form of the dust acoustic wave dispersion relationship that includes ion drag and neutral drag. Generally good agreement is found between the experiment and theoretical model