A study of ions' shear flow instabilities and parallel electron current in pure pair-ion and pair-ion-electron plasmas

The pair-ion plasma has attained special attention due to equal masses and equal but opposite charges. The electrostatic fluctuations with sheared effect are investigated in ideal low-density and low-temperature pure pair-ion (PI) and pair-ion electron (PIE) plasmas in different cases. These instabilities are also studied with homogeneous and inhomogeneous density effects. The growing D'Angelo mode can become the electrostatic instability with shear flow in uniform PIE plasma. It is observed that the shear flow also gives rise to an electrostatic instability in temperature anisotropic pure pair-ion plasma. It is also seen that in pair-ion plasma, the presence of small concentration of electrons results in significant changings in real frequency and growth rate of ion acoustic waves (IAWs). The effect of current driven field aligned flow of electrons on IAWs is also discussed in this article. Kinetic and fluid models are used to study the growth rate of IAWs when both the ionic species have similar shear flow and when both the ionic species have different shear flow. (© 2022 Wiley‐VCH GmbH)