Instantaneous electric field measurements and derived neutral winds at Arecibo

Previously, ion vector velocity measurements at Arecibo required the rotation of the antenna (a 360° rotation takes about 15 minutes) in order to accumulate enough information from different directions. In addition, a least‐squares fitting method or a more sophisticated inversion technique is necessary to determine horizontal velocities. This study reports the first instantaneous long‐duration F region vector velocity measurements in the magnetic meridian plane using the dual‐beam system. This configuration is suitable for measuring the eastward electric field and deriving the meridional neutral wind with very high time resolution. The first results of this experiment presented here seem to show evidence for a gravity wave driven plasma process.