Masood Waqas, Eliasson Bengt, Shukla Padma K
TPPD, PINSTECH, P. O. Nilore, Islamabad, Pakistan.
Phys Rev E Stat Nonlin Soft Matter Phys. 2010 Jun;81(6 Pt 2):066401. doi: 10.1103/PhysRevE.81.066401. Epub 2010 Jun 15.
A generalized set of nonlinear electromagnetic quantum hydrodynamic (QHD) equations is derived for a magnetized quantum plasma, including collisional, electron spin- 1/2, and relativistically degenerate electron pressure effects that are relevant for dense astrophysical systems, such as white dwarfs. For illustrative purposes, linear dispersion relations are derived for one-dimensional magnetoacoustic waves for a collisionless nonrelativistic degenerate gas in the presence of the electron spin- 1/2 contribution and for magnetoacoustic waves in a plasma containing relativistically degenerate electrons. It is found that both the spin and relativistic degeneracy at high densities tend to slow down the magnetoacoustic wave due to the Pauli paramagnetic effect and relativistic electron mass increase. The present study outlines the theoretical framework for the investigation of linear and nonlinear behaviors of electromagnetic waves in dense astrophysical systems. The results are applied to calculate the magnetoacoustic speeds for both the nonrelativistic and relativistic electron degeneracy cases typical for white dwarf stars.
针对磁化量子等离子体，推导了一组广义非线性电磁量子流体动力学（QHD）方程，其中包括与致密天体物理系统（如白矮星）相关的碰撞、电子自旋1/2以及相对论简并电子压力效应。为了说明起见，推导了一维磁声波在存在电子自旋1/2贡献时无碰撞非相对论简并气体中的线性色散关系，以及包含相对论简并电子的等离子体中磁声波的线性色散关系。结果发现，由于泡利顺磁效应和相对论电子质量增加，高密度下的自旋和相对论简并都倾向于使磁声波减速。本研究概述了致密天体物理系统中电磁波线性和非线性行为研究的理论框架。所得结果被应用于计算白矮星典型的非相对论和相对论电子简并情况下的磁声速度。
