Revisit of Ion Acoustic wave in MPD

A new multi-line cusp configured plasma device (MPD) consisting of electromagnets with core material has been constructed with a capability to experimentally control the relative volume fractions of magnetized to unmagnetized plasma volume as well as accurate control on the gradient length scales of mean density and temperature profiles. The electrostatic fluctuations measured using the Langmuir probe radially along the non-cusp region show less than 1% (δn/n< 1%). A controlled experiment on Ion Acoustic waves in the quiescent Argon plasma has been performed in a quiescent Argon plasma of MPD. After this, the strength of amplitude of potential perturbations was increased and given to the grid immersed in the plasma to observe the nonlinearity in the wave. These large potentials increased the amplitude of the IA wave. The properties of ion-acoustic are measured by changing the equilibrium condition of plasma. The equilibrium properties of plasma are changed by increasing the pole magnetic field of the cusp magnetic field. The measured wave amplitude decreased with an increasing magnetic field and after a certain pole magnetic field, the wave disappear. In this article, the probable mechanism of decreasing the amplitude of the ion-acoustic wave has been discussed.