ELECTRON-PLASMA WAVES ON CYLINDRICAL STRUCTURES AND THE CONCEPT OF ANEQUIVALENT DIELECTRIC

The dispersion relation Delta(0)(omega, beta) = 0 of the azymuthally s ymmetric electron surface wave propa gating on a plasma column placed in a glass tube of thickness delta and permittivity epsilon(g) has a f airly complicated form, with several parameters involved in many clust ers of Bessel functions of various orders, kinds and arguments. Much s impler is the dispersion relation Delta(0)(h) (omega, beta) = 0 for th e surface wave on a plasma cylinder in a homogeneous dielectric, but t hat situation is often inapplicable as a model in real experiments. Ho wever, one can reproduce the Delta(0), dispersion curves starting from the Delta(0)(h) ones, conveniently choosing an equivalent glass permi ttivity epsilon (delta, epsilon(g), beta) instead of the constant epsi lon(g). We have proved that this procedure gives acceptable approximat e results. The computations valid for an azimuthally symmetric surface wave are given and the necessary comparisons done.