Slow wave transmission modes of an isotropic inhomogeneous cylindrical hot plasma

The dispersion relations for coupled electromagnetic waves and longitudinal waves propagating along a plasma column are derived and experimentally measured. The `hot' plasma is described by the equations of the two-fluid model which include a gradient pressure term. A quasistatic approximation, E = -grad ϕ, is used in place of the complete electromagnetic equations. The ω-β curves (β is the propagation constant along the column) have been calculated for modes with an azimuthal mode-number of zero and of one. The measurements, performed on the positive column of a mercury vapour discharge, show the presence of many bands of propagation corresponding to large radial mode numbers. The theoretical and experimental results are in agreement.