Dielectric Measurements in Plasma at very High Frequencies (150–200 Mc/s.)

ABSTRACT

Investigations of the variation with frequency of permittivity and conductivity of ionized air and ionized argon in the VHF range are described. Impedance offered to a slab line by the plasma column (of the weakly ionized gas in the form of a plasma slab) is determined from VSWR measurements. The variation of phase constant β, phase velocity ν_p and group velocity ν_g with angular frequency ω of propagating wave are deduced. In the case of ionized air, observations are made in the anomalous region of collision frequency ν = ω and regions of negative group velocity are shown.