ANGEO Annales Geophysicae ANGEO Ann. Geophys. 1432-0576 Copernicus Publications Göttingen, Germany 10.5194/angeo-23-2713-2005 The Double Star magnetic field investigation: instrument design, performance and highlights of the first year's observations Carr C. 1 Brown P. 1 Zhang T. L. 2 Gloag J. 1 Horbury T. 1 Lucek E. 1 Magnes W. 2 O'Brien H. 1 Oddy T. 1 Auster U. 3 Austin P. 4 Aydogar O. 2 Balogh A. 1 Baumjohann W. 2 Beek T. 1 Eichelberger H. 2 Fornacon K.-H. 3 Georgescu E. 5 Glassmeier K.-H. 3 Ludlam M. 1 Nakamura R. 2 Richter I. 3 The Blackett Laboratory, Imperial College London SW7 2BW, UK Space Research Institute, Austrian Academy of Sciences, A-8042 Graz, Austria Institut für Geophysik und extraterrestrische Physik, D-38106 Braunschweig, Germany Ultra Electronics Signature Management Systems Ltd, Hednesford WS12 5QZ, UK Max-Planck-Institut für extraterrestrische Physik, D-85748 Garching, Germany 08 11 2005 23 8 2713 2732 Copyright: © 2005 C. Carr et al. 2005 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://angeo.copernicus.org/articles/23/2713/2005/angeo-23-2713-2005.html The full text article is available as a PDF file from https://angeo.copernicus.org/articles/23/2713/2005/angeo-23-2713-2005.pdf

One of the primary objectives of the Double Star mission is the accurate measurement of the magnetic field vector along the orbits of the two spacecraft. The magnetic field is an essential parameter for the understanding of space plasma processes and is also required for the effective interpretation of data from the other instruments on the spacecraft. We present the design of the magnetic field instrument onboard both of the Double Star spacecraft and an overview of the performance as measured first on-ground and then in-orbit. We also report the results of in-flight calibration of the magnetometers, and the processing methods employed to produce the final data products which are provided to Double Star investigators, and the wider community in general. Particular attention is paid to the techniques developed for removing magnetic interference generated by the solar arrays on the first (equatorial orbiting) spacecraft. Results from the first year of operations are reviewed in the context of combined observations by Double Star and Cluster, and examples given from the different regions visited by the spacecraft to date.