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Annales Geophysicae An interactive open-access journal of the European Geosciences Union
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Volume 36, issue 5 | Copyright
Ann. Geophys., 36, 1285-1302, 2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Regular paper 02 Oct 2018

Regular paper | 02 Oct 2018

Beam tracking strategies for fast acquisition of solar wind velocity distribution functions with high energy and angular resolutions

Johan De Keyser1, Benoit Lavraud2, Lubomir Přech3, Eddy Neefs1, Sophie Berkenbosch1, Bram Beeckman1, Andrei Fedorov2, Maria Federica Marcucci4, Rossana De Marco4, and Daniele Brienza4 Johan De Keyser et al.
  • 1Royal Belgian Institute for Space Aeronomy (BIRA-IASB), Ringlaan 3, 1180 Brussels, Belgium
  • 2Institut de Recherche en Astrophysique et Planétologie (IRAP), Univ. Toulouse, CNRS, UPS, CNES, Toulouse, France
  • 3Charles University, Faculty of Mathematics and Physics, Prague, Czech Republic
  • 4Istituto di Astrofisica e Planetologia Spaziali (INAF/IAPS), Rome, Italy

Abstract. Space plasma spectrometers have often relied on spacecraft spin to collect three-dimensional particle velocity distributions, which simplifies the instrument design and reduces its resource budgets but limits the velocity distribution acquisition rate. This limitation can in part be overcome by the use of electrostatic deflectors at the entrance of the analyser. By mounting such a spectrometer on a Sun-pointing spacecraft, solar wind ion distributions can be acquired at a much higher rate because the solar wind ion population, which is a cold beam that fills only part of the sky around its mean arrival direction, always remains in view. The present paper demonstrates how the operation of such an instrument can be optimized through the use of beam tracking strategies. The underlying idea is that it is much more efficient to cover only that part of the energy spectrum and those arrival directions where the solar wind beam is expected to be. The advantages of beam tracking are a faster velocity distribution acquisition for a given angular and energy resolution, or higher angular and energy resolution for a given acquisition rate. It is demonstrated by simulation that such beam tracking strategies can be very effective while limiting the risk of losing the beam. They can be implemented fairly easily with present-day on-board processing resources.

Publications Copernicus
Short summary
This paper describes "beam tracking", a new technology for measuring velocity distributions in the solar wind with a plasma spectrometer, that allows the order of magnitude speedup in data acquisition needed for studying ion-scale turbulence. The basic idea is that the spectrometer should only sample the energy–elevation–azimuth range where the solar wind is expected to reside. The paper shows how the technique can be implemented and illustrates its performance and robustness through simulation.
This paper describes "beam tracking", a new technology for measuring velocity distributions in...