Kinetic study of electrostatic modes in a Lorentzian Electron-Positron-Ion (EPI) plasma

The propagation and Landau damping of Langmuir Waves (LWs) and Ion-Acoustic Waves (IAWs) in Electron-Positron-Ion (EPI) plasma are investigated using Kinetic theory approach, with all the species to be Kappa or Lorentzian distributed. We observed that the Landau damping rates γ(κ) of Langmuir waves and IAWs in Lorentzian EPI plasma strongly depend upon the spectral index κ i.e., non-thermality parameter, wave number k, the positron temperature T _p and the positron concentration or number density n _p. The Landau damping γ(κ) of Langmuir waves was found to be increased with higher positron temperatures T _p, whereas, that of IAWs was found to increase with lower positron temperatures T _p. Moreover, it was observed γ(κ) of LWs shows a decrease with increase in positron concentration while γ(κ) of IAWs tends to increase. (paper)