Dey Rupak, Banerjee Gadadhar, Misra Amar Prasad, Bhowmik Chandan
Department of Mathematics, Siksha Bhavana, Visva-Bharati University, Santiniketan, 731 235, India.
Department of Mathematics, Burdwan Raj College, University of Burdwan, Burdwan, 713 104, India.
Sci Rep. 2024 Nov 6;14(1):26872. doi: 10.1038/s41598-024-75051-7.
The theory of ion-acoustic solitons in nonrelativistic fully degenerate plasmas and nonrelativistic and ultra-relativistic degenerate plasmas at low temperatures is known. We consider a multi-component relativistic degenerate electron-positron-ion plasma at finite temperatures. Specifically, we focus on the intermediate region where the particle's thermal energy and the rest mass energy do not differ significantly, i.e., . However, the Fermi energy is larger than the thermal energy and the normalized chemical energy ( ) is positive and finite. Two different parameter regimes with and , relevant for astrophysical plasmas, are defined, and the existence of small amplitude ion-acoustic solitons in these regimes are studied, including the critical cases where the known KdV (Korteweg-de Vries) theory fails. We show that while the solitons with both the positive (compressive) and negative (rarefactive) potentials coexist in the case of , only compressive solitons can exist in the other regime . Furthermore, while the rarefactive solitons within the parameter domains of and can evolve with increasing amplitude and hence increasing energy, the energy of compressive solitons reaches a steady state.
非相对论性完全简并等离子体以及低温下的非相对论性和超相对论性简并等离子体中的离子声孤子理论是已知的。我们考虑有限温度下的多组分相对论性简并电子 - 正电子 - 离子等离子体。具体而言，我们关注粒子的热能和静止质量能量相差不显著的中间区域，即 。然而，费米能量 大于热能，且归一化化学能（ ）为正且有限。定义了与天体物理等离子体相关的两种不同参数范围 和 ，并研究了这些范围内小振幅离子声孤子的存在性，包括已知的KdV（科特韦格 - 德弗里斯）理论失效的临界情况。我们表明，在 的情况下，具有正（压缩）势和负（稀疏）势的孤子共存，而在另一种情况 下，仅能存在压缩孤子。此外，在 和 的参数域内，稀疏孤子可以随着振幅增加从而能量增加而演化，而压缩孤子的能量达到稳态。
