Geophysical properties of the ionospheric irregularities responsible for radio scintillation

The properties of F-region ionospheric irregularities are described based on in-situ measurements of the actual waveforms of ion concentration. The spectral properties of the irregularities are discussed. In high, middle and low latitudes most of the irregularities observed fall into a single 'noiselike' category having power spectra which can be approximated by f to the negative n-th power and S to the n-th power, where S is the irregularity scale size and n is approximately 2. Thus the spectral components have a maximum gradient which is almost independent of their size. Other categories of irregularities are also observed occasionally.