Large‐diameter plasma columns produced by surface waves at radio and microwave frequencies

Up to now, the production of plasma columns through the propagation of electromagnetic surface waves had been reported essentially in the microwave range (200 MHz–10 GHz), with tube diameters that extend from 0.5 to 40 mm. Such plasmas can be obtained at much lower frequencies, at least down to 27 MHz. We also present larger plasma column diameters, up to 124 mm, as well as column lengths up to 6 m. The surface wave dispersion and the axial electron density distribution observed under these new conditions are well described by the cold plasma model.