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[en] Satellite-borne sensors were the primary instruments employed to gather data in connection with the International Magnetospheric Study (IMS). However, it is difficult with a limited number of satellites to sample the properties of the magnetosphere in sufficient detail to form a complete picture of the processes taking place. The data obtained with the aid of the satellites are, therefore, supplemented with information provided by means of ground-based sensors. An important element of the IMS ground-based program is the network of incoherent scatter radar stations. A description is presented of the set of parameters which can be measured or derived from incoherent scatter data. Stations which operated during the IMS are identified, and the scheduled dates of coordinated observations during the IMS are given. A catalog of observations actually conducted has been prepared and is available on request

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[en] The Chatanika, Alaska, incoherent scatter radar has been used to measure the spatial variation of auroral ionization. A two-dimensional (altitude, latitude) cross-sectional map of electron densities in the ionosphere is produced by scanning in the geomagnetic meridian plane. The altitutde variation of ionization is used to infer the differential energy distribution of the incident auroral electrons. The latitudinal variation of this energy distribution and the total energy input are obtained by use of the meridian-scanning technique. Examples are shown of observations made during an active aurora

[en] A technique has been developed by which ground-based measurements made by the Chatanika radar can be used to determine the energy distribution of the incident auroral electrons. An altitude profile of electron density is deconvolved into an incident energy spectrum by use of a library of ionization production profiles for monoenergetic electrons. The accuracy of the method has been assessed by application to synthetic ionization profiles produced by known electron energy distributions. Results indicate that the incident energy distribution can be recovered with high precision (deviations typically < 25%) for incident energies between 1 and 12 keV. The method has been applied to several density profiles obtained at Chatanika during auroral activity. (Auth.)

[en] F region ion temperature measurements were made by the Chatanika and Millstone Hill incoherent scatter radars as part of the Magnetosphere-Ionosphere-Thermosphere Radar Studies program of coordinated high-latitude observations. At both radars, periods of enhanced ion temperature associated with Joule heating events were detected. A regular feature of the observations was the existence of larger and longer lasting temperature enhancements in the morning sector as contrasted with the evening sector during periods of comparable electric field magnitudes. Because the ion temperature increases in proportion to the square of the vector difference between the ion and neutral velocities, the morning/evening temperature enhancement asymmetry implies a morning/evening neutral wind asymmetry. The neutral wind in the evening must be more closely aligned to the ion flow vector. This might arise as a consequence of the higher plasma density in the evening sector, enabling the ions to set the neutral air in motion. Comparison of the simultaneous plasma density and ion velocity measurements with the ion temperature data supports the foregoing explanation for the observed greater morning sector temperature enhancements