How the Saint Santin incoherent scatter system paved the way for a French involvement in EISCAT

摘要

This paper relates the development of a French incoherent scatter systemwhich started its operations in 1965. This development took place severalyears after the initial implementation of such systems in the United States,in Peru and in the United Kingdom. The French system, owing to its bistaticconfiguration and the use of continuous waves, differed from the previousones. These characteristics yielded signals of excellent spectral quality,unravelling the possibility of inferring physical parameters (Doppler shift,average ion mass) out of reach, at that time, of other systems. Thepossibility of making ion drift vector measurements led to extend the systeminto a quadristatic configuration. The multiple capabilities offered by theincoherent scatter technique, notably as concerns the thermodynamicalproperties of the ionosphere and of the thermosphere, led further the Frenchcommunity to a project of embarking an incoherent scatter radar on board aship. Taking account of a project of a Scandinavian auroral zone radar andof the considerable interest of the study of auroral zone electrodynamics,the French community abandoned the idea of the ship and expressed aninterest in joining the Scandinavian project in conjunction with Germany andthe United Kingdom.