Effect of quantization and positron concentration on shielding potentials in electron‐positron‐ion plasma

Abstract

The kinetic theory of plasma has been employed to compute the test‐charge potential distributions accounting for quantization effects in magnetized electron‐positron‐ion (EPI) plasmas. In this regard, the degenerate positrons and electrons are assumed to follow the Fermi‐Dirac distribution, while inertial ions are modelled by Maxwellian velocity distribution. By solving the Fourier‐transformed Vlasov–Poisson equations, a modified dielectric function and electrostatic potential is obtained. By imposing various constraints on the test‐charge speed, the potential profile has been analysed in terms of Debye–Hückel (DH), far‐field (FF), and wake‐field (WF) potentials. It has been found that the amplitude of DH and FF potentials increases by the inclusion of quantization effects, and it becomes the opposite for the WF potential profile. Furthermore, the variation of positron concentration significantly affects the DH, FF, and WF potentials. The present findings are important to understand the shielding phenomenon in degenerate multi‐species plasmas.

The energy dissipation of a test-charge particle within a dense, degenerate electron- positron-ion plasma

“…Different conditions can be imposed on the test-charge speed for obtaining the Debye potential, the farfield potential and wakefield potential. These potentials have been studied [39] in details to show the response of static, slow, and resonating test charges. As an example, if the test charge is static (v T = 0 ⟹W(C i ) ; 1), then it will be shielded by all the plasma species, i.e., the electrons, positrons and ions.…”

“…Hussain et al [38] explained the phenomenon of screening due to a single test charge and presented its potential distribution in a quantized electron-ion plasma with electron Landau quantization. Quite recently, Hafeez et al [39] extended the work [38] to examine the potential distribution around the test charge for different test charge speeds and electron-positron quantizations. Since the electron-positron quantization does affect the energy loss mechanism in EPI plasmas, a more detailed investigation is required to highlight the important role of positrons and for the completeness of the topic.…”