Effect of superthermal electrons on the Quantum electron acoustic double layers in dense astrophysical plasmas

Abstract: Electron acoustic double layers (EADLs) have been investigated in four component unmagnetized dense quantum plasmas consisting of stationary background ions and two electron populations, cold and hot, with the superthermal kappa distributed electrons. Using the quantum hydrodynamic (QHD) model and the reductive perturbation technique, a generalized Korteweg de Vries (KdV) equation was derived, and stationary analytical solutions were obtained. The analysis revealed that superthermal electrons substantially influence the amplitude, width, and polarity of EADLs. Numerical results indicated that decreasing the spectral index kappa or increasing the relative density of kappa electrons to hot electrons intensifies nonlinear effects, producing stronger compressive and rarefactive structures. It is also found that kappa plays a more dominant role than the density ratio in controlling EADL properties in dense astrophysical environments.