Hydromagnetic surface waves along compressible cylindrical flux tubes with steady flows

Abstract

Hydromagnetic surface waves along a moving compressible plasma surrounded by a stationary plasma medium are investigated. The surface waves propagating along a cylindrical column should decay in amplitude, in a direction normal to the interface, i.e radially. Waves with amplitude proportional to the Bessel function J1(x) and Hankel function H1(x) do not, generally, represent a surface wave as reported by Satyanarayanan. The correct dispersion relation for a cylindrical plasma column with steady flow is obtained and the results are discussed for the isolated photospheric flux tubes, coronal streamers and solar wind flow tubes. It was found that while flux tubes support surface waves, the coronal streamers and solar wind flow tubes do not support surface waves for the parameters we have chosen.