351-355Many of the great advances in ionospheric research in the last 40 years have come about because of improvements in technology, especially through modern electronics and optical and computational advances. The advent of the space age, with satellite and rocket capability, has provided a major improvement in our ability to measure the upper atmosphere and the ionosphere. The construction of realistic theoretical models of the upper atmosphere and the ionosphere have made great strides in our understanding of the relative effects of the various driving forces on the ionosphere. These are discussed in some detail along with prospects for future breakthroughs in technology which will benefit ionospheric research. One particularly significant example to be described in detail is the improvement of knowledge of the now well known equatorial anomaly, briefly described in S. K. Mitra’s book [The Upper Atmosphere (The Asiatic Society, Calcutta, India), 1947, 1952]. During the course of the 1950s, and even to the present date, the anomaly in F2-region electron density has been an active area of study, with much of this research being done by Indian scientists. Despite the many experimental results from both ground-based and satellite-borne sounders, and total electron content measurements, clearly showing the variability of the equatorial anomaly, it was not until the 1980s when a model of the low latitude ionosphere derived from first principles was able to reasonably well reproduce the observations discussed in Mitra’s book. Other examples of areas still needing additional experimental and theoretical research are also described
