Electric Field Measurement on the Akebono (EXOS-D) Satellite

Abstract

Electric field detectors (EFD) on the EXOS-D (Akebono) satellite measure the vector electric field by both the standard double probe technique (EFD-P) and the newly developed ion beam technique (EFD-B). The EFD-P system has been proven to generate high quality data owing to its antenna alignment which is perpendicular to the sun-earth direction at any phase of the satellite spin. The EFD-B system has not yet been fully operated and is ready for a suitable orbital phase for beam experiments. This paper describes the instrumentation and preliminary observed results obtained by the EFD-P such as the Langmuir characteristics of the probe in the plasmasphere and the convection electric field in the auroral ionosphere. An intense electric field has been observed between the region 1 and 2 current on the morning side. Close to the mid-day meridian, fluctuating electric fields that are likely to be related in terms of a cusp/cleft structure were observed.