Nonlinear Excitations in Strongly-Coupled Fermi-Dirac Plasmas

TL;DR

This paper investigates how various quantum and Coulomb interactions influence large-amplitude nonlinear wave structures in strongly-coupled Fermi-Dirac plasmas, highlighting differences between nonrelativistic and relativistic degeneracy regimes.

Contribution

It combines quantum hydrodynamics with the Sagdeev pseudopotential method to analyze nonlinear excitations considering multiple interaction effects in Fermi-Dirac plasmas.

Findings

Strong interactions significantly affect nonlinear wave dynamics in nonrelativistic regimes.

First-order Coulomb and exchange corrections are more impactful in nonrelativistic degeneracy.

In relativistic regimes, quantum tunneling and Pauli exclusion dominate nonlinear wave behavior.

Abstract

In this paper we use the conventional quantum hydrodynamics (QHD) model in combination with the Sagdeev pseudopotential method to explore the effects of Thomas-Fermi nonuniform electron distribution, Coulomb interactions, electron exchange and ion correlation on the large-amplitude nonlinear soliton dynamics in Fermi-Dirac plasmas. It is found that in the presence of strong interactions significant differences in nonlinear wave dynamics of Fermi-Dirac plasmas in the two distinct regimes of nonrelativistic and relativistic degeneracies exist. Furthermore, it is remarked that first-order corrections due to such interactions (which are proportional to the fine-structure constant) are significant on soliton dynamics in nonrelativistic plasma degeneracy regime rather than relativistic one. In the relativistic degeneracy regime, however, these effects become less important and the electron quantum-tunneling and Pauli-exclusion dominate the nonlinear wave dynamics. Hence, application of non-interacting Fermi-Dirac QHD model to study the nonlinear wave dynamics in quantum plasmas such as compact stars is most appropriate for the relativistic degeneracy regime.