Asam M T, Shah H A, Masood W
Department of Physics, Forman Christian College, Ferozepur Road, Lahore, 54600, Pakistan.
Government Waris Shah Associate College, Jandiala Sher Khan, Sheikhupura, 39350, Pakistan.
Sci Rep. 2025 Feb 26;15(1):6853. doi: 10.1038/s41598-024-82416-5.
The study of dense degenerate plasmas at extreme temperatures and densities motivates the investigation of relativistic and ultrarelativistic regimes. In this paper, we are presenting a comprehensive study of the linear and nonlinear propagation characteristics for kinetic Alfven acoustic waves (KAAW) at relativistic and ultra relativistic Fermi energies with small temperature corrections. The linear wave propagation of fast and slow modes for relativistic KAAW are studied and a comparative analysis of both the modes is plotted for relativistic, ultrarelativistic and nonrelativistic regimes. It has been investigated that for constant magnetic fields, the phase velocity of these waves decreases due to an increase in both the specific heat and thermal pressure at low plasma beta values and KAAW propagate more efficiently in outer regions with lower specific heat than in denser inner regions of neutron stars. Various theoretical approaches like Sagdeev pseudopotential approach, dynamical analysis, and finite amplitude expansion method are employed to analyse the nonlinear relativistic and ultrarelativistic KAAW. Phase space trajectories have been plotted to study the nonlinear structures corresponding to arbitrary amplitude perturbations. The existence regions of solitary kinetic Alfven acoustic waves (SKAAW) and the physical reasons for their dependence on different parameters have also been shown. Possible applications are envisaged in the intense laser-matter interactions, plasma photonics, dense astrophysical objects like the interior state of terrestrial planets, neutron stars, and white dwarfs where relativistic effects dominate the microscopic scale and may have macroscopic consequences.
对处于极端温度和密度下的致密简并等离子体的研究推动了对相对论和超相对论区域的研究。在本文中，我们对具有小温度修正的相对论和超相对论费米能量下的动力学阿尔文声波（KAAW）的线性和非线性传播特性进行了全面研究。研究了相对论KAAW的快波和慢波的线性波传播，并绘制了相对论、超相对论和非相对论区域中这两种模式的对比分析图。研究发现，对于恒定磁场，在低等离子体β值下，由于比热和热压力的增加，这些波的相速度会降低，并且KAAW在比中子星内部密度较低的比热区域更有效地传播。采用了各种理论方法，如萨德耶夫赝势方法、动力学分析和有限振幅展开方法来分析非线性相对论和超相对论KAAW。绘制了相空间轨迹以研究对应于任意振幅扰动的非线性结构。还展示了孤立动力学阿尔文声波（SKAAW）的存在区域及其依赖于不同参数的物理原因。在强激光与物质相互作用、等离子体光子学、致密天体物理对象（如类地行星、中子星和白矮星的内部状态）中设想了可能的应用，在这些对象中相对论效应在微观尺度上占主导地位并且可能产生宏观后果。
