Studies of the F-Region by the Incoherent Backscatter Method

The Millstone Hill radar facility operated by M.I.T. Lincoln Laboratory has made measurements of the distribution of electrons in the F-region of the ionosphere by observing the weak incoherent backscatter signal. These measurements were first made early in 1960 and were continued throughout 1961 on a routine basis at least once a week. This report presents alI the electron density profiles measured up to the end of 1961. Results of spectral analyses of the signals made early in 1962 are also given. The distribution of electrons above the peak of the F-region has been a subject of special study. On the basis of the results obtained to date the conclusions reached are: (a) the scale height of the electron density increases with height, (b) the ion temperature is not very dependent on height, though it does show a marked diurnal variation, (c) the election-to-ion temperature ratio is 1:1 during the hours of darkness, but during the daytime it increases too peak value ~1.6:1 around noon and (d) the scattering cross section for the electrons is close to the expected value when alIowance is made for (c)