Slowly moving test charge in a two-electron component non-Maxwellian plasma

Potential distributions around a slowly moving test charge are calculated by taking into account the dynamics of electron-acoustic waves (EAWs) in an unmagnetized plasma. The hot electrons are assumed to be suprathermal and obey the Kappa distribution function, whereas the cold inertial electrons are described by the Vlasov equation with a Maxwellian equilibrium distribution, and the positive ions form a static neutralizing background. The test charge moves slowly in comparison between both the hot and cold electron thermal speeds and is therefore shielded by the electrons. This gives rise to a short-range Debye-Hückel potential decaying exponentially with distance and to a far field potential decaying as inverse third power of the distance from the test charge. The results are relevant for both laboratory and space plasma, where suprathermal hot electrons with power-law distributions have been observed.