ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Springer Verlag Göttingen, Germany 10.1007/s00585-997-0542-z First results from the plasma composition spectrometer PROMICS-3 in the Interball project Sandahl I. 1 Barabash S. 1 Borg H. 1 Budnik E. Yu. 2 Dubinin E. M. 2 Eklund U. 1 Johansson H. 1 Koskinen H. 3 Lundin K. 1 Lundin R. 1 Moström A. 1 Pellinen R. 3 Pissarenko N. F. 2 Pulkkinen T. 3 Toivanen P. 3 Zakharov A. V. 2 Swedish Institute of Space Physics, PO Box 812, S-981 28, Kiruna, Sweden Space Research Institute, Profsoyuznaya 84/32, 117 810 Moscow GSP-7, Russia Finnish Meteorological Institute, PO Box 503, SF 00 101 Helsinki, Finland 31 05 1997 15 5 542 552 Copyright: © 1997 I. Sandahl et al. 1997 © European Geosciences Union 1997 This article is available from https://angeo.copernicus.org/articles/15/542/1997/angeo-15-542-1997.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/15/542/1997/angeo-15-542-1997.pdf

PROMICS-3 is a plasma experiment flown in the Russian project Interball. It performs three-dimensional (3D) measurements of ions in the energy range 4 eV–70 keV with mass separation and of electrons in the energy range 12 eV–35 keV. The Interball project consists of two main satellites, the Tail Probe and the Auroral Probe, each with one subsatellite. The Interball Tail Probe was launched on 3 August 1995, into a 65° inclination orbit with apogee at about 30 R<sub>E</sub>. Both main satellites carry identical PROMICS-3 instruments and thus direct comparisons of the particle distributions will be possible once the Auroral Probe is launched. Furthermore, PROMICS-3-Tail is the first instrument measuring the 3D ion distribution function in the magnetospheric boundary layers at high latitudes. In this paper we describe the PROMICS-3 instrument and show initial results from the Tail probe, measurements of the magnetosheath, plasma sheet, and ring current plasmas.