Flowing dusty plasma experiments: Generation of flow and measurement techniques

TL;DR

This paper presents experimental methods for generating and measuring dust fluid flows in a dusty plasma, comparing three techniques and analyzing the forces involved, to facilitate studies of plasma excitations.

Contribution

It introduces and compares three distinct methods for generating and measuring dust flows in a laboratory dusty plasma device, including their advantages and limitations.

Findings

Flow velocities estimated by three techniques show good agreement.

Neutral drag force quantified for flow generation and attenuation.

Techniques enable detailed study of plasma collective excitations.

Abstract

A variety of experimental techniques for the generation of subsonic/supersonic dust fluid flows and means of measuring such flow velocities are presented. The experiments have been carried out in a $\Pi-$shaped Dusty Plasma Experimental (DPEx) device with micron size kaolin/Melamine Formaldehyde (MF) particles embedded in a background of Argon plasma created by a direct current (DC) glow discharge. A stationary dust cloud is formed over the cathode region by precisely balancing the pumping speed and gas flow rate. A flow of dust particles/fluid is generated by additional gas injection from a single or dual locations or by altering the dust confining potential. The flow velocity is then estimated by three different techniques, namely, by super Particle Identification (sPIT) code, Particle Image Velocimetry (PIV) analysis and the excitation of Dust Acoustic Waves (DAWs). The results obtained from these three different techniques along with their merits and demerits are discussed. An estimation of the neutral drag force responsible for the generation as well as the attenuation of the dust fluid flow is made. These techniques can be usefully employed in laboratory devices to investigate linear and non-linear collective excitations in a flowing dusty plasma.