MHD waves within noncommutative Maxwell theory

• Published in: Physics letters. B Vol. 650; no. 1; pp. 90 - 96
• Main Authors: Bourouaine, S., Benslama, A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 21.06.2007; Elsevier Science
• Subjects: CMB; Exact sciences and technology; MHD waves; Noncommutativity; Nuclear physics; Physics; The physics of elementary particles and fields; MHD waves; CMB; Noncommutativity; Alfven waves; Magnetohydrodynamics; Deformation; Homogeneous plasma; Cosmic background radiation; Compressible plasma; Baryons; Phase velocity; Wave propagation; Physical model; S waves; Electromagnetic waves; High field; Magnetic fields; Noncommutative space; Noncommutative theory
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/j.physletb.2007.04.033

In the presence of a strong uniform magnetic field, we study the influence of space noncommutativity on the electromagnetic waves propagating through a quasi-static homogeneous plasma. In this treatment, we have adopted a physical model which considers plasma as quasi-neutral single fluid. By using noncommutative Maxwell theory, the ideal magnetohydrodynamics (MHD) equations are established, in which new equilibrium conditions are extracted. As an empirical study, some attractive features of MHD waves behavior are investigated. Furthermore, it is shown that the presence of space noncommutativity enhances slightly the phase velocity of the incompressive shear Alfvén waves. In a compressible plasma, the noncommutativity plays the role of an additional compression on the medium, in which its relevant effect on the fast mode occurs for highly oblique branches, while the low effect appears when the propagations are nearly parallel or anti-parallel. In addition, it turned out that the influence of space deformation on the slow modes is ∼103 times smaller than that on the fast modes. The space noncommutativity effect on the slow waves is negligible in low plasma β value, and could appear when β is higher than 0.1, thus the extreme modification occurs for oblique slow waves propagating with angles between 30° and 60°. Finally, we comment on the possible effect of such waves on CMB spectrum in photon–baryon plasma.