The effect of anisotropy on the propagation of linear compressional waves in magnetic flux tubes: Applications to astrophysical plasmas

¹ Space & Atmosphere Research Center (SPARC), Dept. of Applied Mathematics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH, UK
² Babes-Bolyai University, Dept. of Theoretical Physics, 1 Kogalniceanu, 3400-Cluj Napoca, Romania

Corresponding author: I. Ballai, i.ballai@sheffield.ac.uk

Received: 24 June 2003
Accepted: 6 November 2003

Abstract

The propagation of linear compressional waves is studied in magnetic flux tubes. The plasma inside and outside the tube is considered to be rarefied which confers an anisotropic character to the plasma. The anisotropy appears at different temperatures for parallel and perpendicular directions relative to the ambient magnetic field. The theoretical results are applied to study the effects of anisotropy and equilibrium steady flow on wave propagation in structures such as coronal plumes, the geomagnetic tail and anisotropic astrophysical jets. The obtained results show that the internal and/or external anisotropy has a very important effect on the propagation of linear compressional waves. The presence of a steady equilibrium flow in certain applications can change dramatically the propagation of the modes.