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 (&ohgr;<&OHgr;i,k&rgr;i≤1) waves travelling in E¿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 4.4¿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. ¿ American Geophysical Union 1992