Spectral characteristics of fluctuations in laboratory plasma simulating features of bottom side equatorial spread-F

Spectral characteristics of fluctuations in laboratory plasma under conditions similar to those obtained in equatorial F-region plasma, are presented. Essential characteristics of the bottom side of the night time equatorial F-region plasma, viz., density gradient antiparallel to gravity and perpendicular to the magnetic field, and magnetized electrons and ions are simulated in a toroidal laboratory plasma, where curved magnetic field produces effective gravity. Low frequency (ω < Ωi, kρi, much-lt 1) waves travelling in E x B direction are observed. The one dimensional k-spectrum (S(k) ∞ kn) of density fluctuations exhibits two marked slopes with indices n = -2.3 ± 0.3 and x4.4 ±0.2. Results are similar to the in-situ measurements in F-region and support theoretical predictions and numerical simulations based on Rayleigh-Taylor and universal drift instabilities