A coordinated set of Atmospheric Explorer E (AE‐E) satellite in situ, VHF radar backscatter, and scintillation measurements performed during 1977 over a common ionospheric volume is used to study the relationship between the plasma depletions or bubbles, the extended 3‐m irregularity structures known as plumes and bursts of scintillation activity or patches in the nighttime equatorial F region. It is shown that in the early evening hours saturated VHF and UHF scintillation and 3‐dB fluctuations (propagation path in the east‐west plane where the effect of anisotropy is least) at 1.54 GHz are obtained in association with strong 50‐MHz radar backscatter, implying near simultaneous (∼min) excitation of large scale (∼km to 100 m) and 3‐m irregularities. In this early developed phase of irregularities, the AE‐E in situ measurements detect strong fluctuations of ion concentration with very sharp spatial gradients. The power spectra of these fluctuations in the scale length range of 10 km‐100 m conform to a power law variation with one‐dimensional spectral index ∼1.5. The postmidnight period, on the other hand, is found to be characterized by an absence of radar backscatter and presence of only marginal GHz scintillation activity. However, strong VHF scintillations and somewhat weaker UHF activity is found to persist. The AE‐E measurements indicate that during the late phase, the spatial gradients of ion concentration become shallower and the spectral intensity of the irregularities <500 m decreases by about two orders of magnitude as compared with that recorded during the onset phase. The irregularity spectrum conforms to a quasi‐gaussian description with correlation lengths of the order of a kilometer, which corresponds to the Fresnel dimensions of VHF scintillation observations. The implications of the observed spatial structures and the level of ambient concentration on the generation of 3‐m irregularities and scintillation modeling are discussed.