Abstract
Abstract. The purpose of these historical notes is to present the early history of the Jicamarca Radio Observatory (JRO), a research facility that has been conducting observations and studies of the equatorial ionosphere for more than 50 years. We have limited the scope of these notes to the period of the construction of the observatory and roughly the first decade of its operation. Specifically, this period corresponds to the directorships under Kenneth Bowles, Donald Farley, and Tor Hagfors and the first period of Ronald Woodman, i.e., the years between 1960 and 1974. Within this time frame, we will emphasize observational and instrumental developments which led to define the capabilities of the Jicamarca incoherent scatter (IS) radar to measure the different physical parameters of the ionosphere. At the same time, we partially cover the early history of the IS technique which has been used by many other observatories built since. We will also briefly mention the observatory's early and most important contributions to our understanding of the physical mechanisms behind the many peculiar phenomena that occur at the magnetic Equator. Finally, we will put special emphasis on the important developments of the instrument and its observing techniques that frame the capabilities of the radar at that time.
Highlights
One year after the launching of Sputnik, a US scientist, Bill Gordon (1918–2010; see Fig. 2a), a professor at Cornell University, proposed, in a paper published in the Proceedings of the IRE (Gordon, 1958), that the most important characteristics of the free-electron gas that conformed the ionosphere could be measured from the ground, competing in this way with the measurements that were performed by satellites
The technique was based on the scattering of radio waves by free electrons, i.e., by those electrons that were detached from the few atoms that constitute the atmosphere at these altitudes
This was an important hypothesis and led to the selection of the site of what eventually became the Jicamarca Radio Observatory, since in order to detect these periodicities in the incoherent scatter (IS) signals, the radar needed to be pointed in a direction close to perpendicular to the magnetic field lines
Summary
In 1957, the Soviet Union had launched Sputnik (Fig. 1) and with it the beginning of the Space Age (e.g., Tikhonravov, 1994). Gordon’s efforts to publish and promote his idea, Ken Bowles (1929–2018; see Fig. 2b), a former student at Cornell and scientist of the Central Radio Propagation Laboratory of the National Bureau of Standards (NBS), was gathering support to experimentally obtain echoes from the ionospheric electrons using the technique. He learned about the existence of a powerful 41 MHz transmitter at a NBS facility at Long Branch, Illinois. We leave the more recent developments and scientific contributions to a future publication, which will complement the full history of the observatory (many more years in comparison)
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