Theoretical investigations on propagating and growing modes in a pair plasma having dust grains

Considering a homogenous positron-electron pair plasma, we investigate the propagating and growing modes in the plasma under the presence of heavy dust particles that are negatively charged. Since these dust grains are massive particles, they do not oscillate but contribute to the excitation of the waves by providing restoring force. Normal mode analysis is used to calculate the dispersion relations based on which we analyze the propagating and growing modes in the plasma. Two types of the modes are found to occur whose phase velocities are studied under the effects of temperatures and drift velocities of the electrons and the positrons.