Altair: an incoherent scatter radar for equatorial spread F studies

We report preliminary results on 1-m equatorial spread F irregularities obtained with a high-power VHF backscatter radar located at equatorial latitudes. The field experiment was conducted at Kwajalein Atoll, Marshall Islands, during August 1977. The examples, which include both incoherent scatter measurements and backscatter from equatorial spread F irregularities, illustrate the usefulness of a fully steerable radar for equatorial spread F studies. The backscatter observations at 155.5 MHz are not consistent with the scattering model proposed by Woodman and Basu (1978), which includes a cutoff near the ion gyroradius. The results obtained thus far also indicate that the collisional Rayleigh-Taylor instability is probably the principal mechanism producing equatorial spread F.