Low frequency electrostatic fluctuations (ω < Ωi) travelling in E×B direction are observed in a laboratory plasma simulating conditions similar to night time equatorial F‐region. The density and potential fluctuations in the region of the plasma where effective g parallel to density gradient ∇n has similar spectral characteristics to that of the results of our earlier experiment of bottom side of equatorial spread F. The k‐spectrum of density in this region of plasma exhibits two marked slopes with indices n= −2.5±0.3 and −4.6± 0.3 where as the potential spectrum exhibits one slope with index −5.2± 0.2. The fluctuations are generated in the region where ∇n is antiparallel to g and appear in the other region due E×B motion. Results are in agreement with in‐situ measurements in F‐region, theoretical predictions and numerical simulation of Rayleigh‐Taylor and drift wave instabilities.