Effect of external magnetic field and dust grains on the properties of Ion Acoustic Waves

TL;DR

This experimental study investigates how external magnetic fields and dust grains influence ion-acoustic wave properties in plasma, revealing that magnetic fields increase wave velocity while dust decreases it, aiding plasma diagnostics.

Contribution

The paper presents new experimental insights into the effects of magnetic fields and dust on ion-acoustic waves in plasma, with potential applications in plasma diagnostics.

Findings

Magnetic field increases phase velocity of IAWs.

Dust grains decrease phase velocity of IAWs.

Magnetic field affects wave damping significantly.

Abstract

An experimental study to investigate the effect of an external magnetic field on the propagation of ion-acoustic waves (IAWs) has been carried out in hydrogen plasma containing two-temperature electrons and dust grains. A low-pressure hot cathode discharge method is opted for plasma production. The desired two electron groups with distinct temperatures are achieved by inserting two magnetic cages with a cusp-shaped magnetic field of different surface field strengths in the same chamber. The dust grains are dropped into the plasma with the help of a dust dropper, which gain negative charges by interacting with the plasma. The IAWs are excited with the help of a mesh-grid inserted into the plasma. A planar Langmuir probe is used as a detector to detect the IAWs. The time of flight technique has been applied to measure the phase velocity of the IAWs. The results suggest that in the presence of a magnetic field, the phase velocity of IAWs increases, whereas introducing the dust particles leads to the lower phase velocity. The magnetic field is believed to have a significant effect on the wave damping. This study will aid in utilising IAWs as a diagnostic tool to estimate plasma parameters in the presence of an external magnetic field. Moreover, the study might be useful for estimating the relative ion concentrations in a two positive ion species plasma, as well as the relative concentration of the negative ions in the presence of an external magnetic field.