New Rocket Measurement of Ionospheric Currents Near the Geomagnetic Equator

Several rocket-borne magnetometers were flown recently near the geomagnetic equator. The record from one of these flights, made at 161° west longitude and 00° latitude, on 18 October 1957, is presented here as new evidence for the existence of electrical currents in the lower ionosphere.1,2 The total-field magnetometer used in the flights was of the nuclear free-precession type.3 The scalar magnitude of the earth's magnetic field is obtained in terms of the precession frequency (ƒ) of the proton, in this field, and the gyromagnetic ratio of the proton (γ); The magnetometer, developed in this laboratory for small rocket use, was a lightweight version of a balloon-carried instrument, previously described.4