Anthony van Eyken

Ionospheric local model and climatology from long-term databases of multiple incoherent scatter radars

Empirical ionospheric local models have been developed from long-term data sets of seven incoherent scatter radars spanning invariant latitudes from 25 to 75 in American, European and Asian longitudes at Svalbard, Tromso, Sondrestrom, Millstone Hill, St. Santin, Arecibo and Shigaraki. These models, as important complements to global models, represent electron density, ion and electron temperatures, and ion drifts in the E and F regions, giving a comprehensive quantitative description of ionospheric properties. A case study of annual ionospheric variations in electron density and ion temperature is presented based on some of these models. Clear latitudinal, longitudinal, and altitude dependency of annual and semiannual components are found.

AMISR the advanced modular incoherent scatter radar

AMISR is a modular, mobile, UHF radar facility used by scientists and students from around the world to conduct studies of the upper atmosphere and to observe space weather events. SRI International, under a grant from the National Science Foundation, is leading the collaborative effort in the development and operation of AMISR. The novel modular configuration allows for relocating the radar to study upper atmospheric activity at different locations around the globe. Remote operation and electronic beam steering allow researchers to operate and position the radar beam on a pulse-to-pulse basis to accurately measure and glean new information from rapidly changing space weather events.

Fiftieth Anniversary of the First Incoherent Scatter Radar Experiment

In the 11 November 2008 issue of Eos (89(46), 458), Henry Rishbeth asked whether the years 2008–2010 feature any important anniversaries in solar-terrestrial physics other than those he mentioned. One such milestone is the fiftieth anniversary of the first incoherent scatter radar (ISR) experiment. At a Cornell University (Ithaca, N.Y.) departmental seminar in the spring of 1958, William Gordon showed that a powerful radar system could detect the uncorrelated and extremely weak scattered signals from individual ionospheric electrons. This process is called incoherent scatter, and studying the properties of the resulting radar echoes can reveal information about the density, temperature, and velocity of ionospheric particles. Gordon discussed this idea with Ken Bowles, a recent Ph.D. graduate of Cornell, and in a few weeks Bowles built a large but inexpensive antenna array that he connected to an existing transmitter near Havana, Ill. Using this crude radar (the data processing consisted of taking a time exposure photograph of the signal amplitude displayed on an oscilloscope), Bowles successfully measured an incoherently scattered signal on 21 October 1958. By a happy coincidence, 21 October was also the day that Gordon gave his first formal talk on the ISR concept at an International Union of Radio Science (URSI) conference at Pennsylvania State University. After calling Bowles for an update on his experiment, Gordon presented his research and added the dramatic and newsworthy note to the end of his talk on the success of the first ISR experiment!