Simultaneous Electric Field Measurements Made in the Auroral Ionosphere by Using three Independent Techniques

Abstract

Two Skylark rockets were launched from the range of the European Space Research Organization (ESRO) near Kiruna on February 14, 1970, at 17.15 CET and on April 2 at 02.46 for investigation of electric fields. Each rocket carried an electric double‐probe experiment, a Langmuir probe, an experiment to detect the influence of the plasma drift on the wake of the rocket, a Geiger‐Müller counter, and finally a barium cloud experiment. Three of these (double‐probe, wake experiment, and barium cloud) provided independent information on the ambient electric field. The present paper deals with the initial results of these three electric field experiments. In the first flight, which took place under slightly disturbed conditions (+40 γ), all methods indicated a roughly northerly field of about 22 mv/m. In the second flight (under quiet conditions), a southerly field between 3 and 6 mv/m was observed by the different experiments. The direction of the plasma drift derived from the measured orientation of the wake of the rocket agrees within 10° with that derived from the double‐probe results and the barium cloud observations. Estimates of electron density and temperature were obtained from the operation of the double‐probe system in different modes. These electron density values were in good agreement with those derived from the ionosonde data and from the Langmuir‐probe data.