Abstract
Considering the basic equations of plasma and neutral fluids, it is shown, theoretically, how neutral dynamics gives rise to various modes in inhomogeneous, magnetized, and partially ionized plasma observed in space as well as in laboratory plasma. The most general dispersion relation which can describe almost all the modes in the system has been obtained. We have shown that the presence of relative velocity between ions and neutrals, compressibility nature of neutrals and gravity gives rise to a few new low frequency modes. The sources of free energy for the onset of various modes are identified. The effect of coupling of neutral dynamics with plasma pinching force (
J ×
B) has been highlighted. It is shown that the phase velocities and the growth rates are very sensitive to the ratio of neutrals with ions and the scale heights associated with inhomogeneities. The potential application of the theoretical results is discussed.