• DOI:10.1051/0004-6361/201937259
• Corpus ID: 224966409

The Solar Orbiter Solar Wind Analyser (SWA) suite

@article{Owen2020TheSO,
  title={The Solar Orbiter Solar Wind Analyser (SWA) suite},
  author={Christopher J. Owen and Renou Bruno and Stefano Livi and Philippe Louarn and K. al Janabi and Fr{\'e}d{\'e}ric Allegrini and Carine Amoros and Rituparna Baruah and Alain Barthe and Matthieu Berthomier and S. Bordon and C. Brockley-Blatt and Clement Brysbaert and Giuseppe E. Capuano and M. Collier and Rossana DeMarco and Andr{\'e}i Fedorov and John Ford and Vito Fortunato and Isabelle Fratter and A. B. Galvin and Barry Hancock and David Heirtzler and D. O. Kataria and Lynn M. Kistler and Susan T. Lepri and Gene Lewis and C. E. Loeffler and W. Marty and Romain Mathon and Alice Mayall and Giacomo Mele and Keiichi Ogasawara and Marco Orlandi and Anne Pacros and Emmanuel Penou and Steve Persyn and Marie Petiot and Mark L.F. Phillips and L. Přech and Jim M. Raines and M von Reden and Alexis P. Rouillard and A. Rousseau and J. Rubiella and H. C. S{\'e}ran and Alton Spencer and Jason Thomas and J. Trevino and Daniel Verscharen and Peter Wurz and A. Alapide and Leonardo Amoruso and Nicolas Andr{\'e} and Chandrasekhar Reddy Anekallu and Vito Arciuli and Kelly L Arnett and Raffaele Ascolese and C. Bancroft and Phil A. Bland and Michael Brysch and Raimondo Calvanese and Marco Maria Castronuovo and I Cermak and D. Chornay and Scott Clemens and John Coker and Glyn A. Collinson and Raffaella D’Amicis and Iannis Dandouras and Richard Gillham Darnley and Douglas Davies and G. Davison and Ada Nelly De los Santos and Pierre Devoto and Greg Dirks and Eric Matthias Edlund and Andrew N. Fazakerley and Mark Ferris and Colin Frost and G. Fruit and Christian Garat and Vincent G{\'e}not and W. F. Gibson and Jason A. Gilbert and V. de Giosa and S. Gradone and M. R. Hailey and Timothy S. Horbury and Tom Hunt and Christian Jacquey and M. Johnson and Beno{\^i}t Lavraud and A. Lawrenson and F. Leblanc and Walter L. Lockhart and Milan Maksimovi{\'c} and A. Malpus and Federica Marcucci and Christian Xavier Mazelle and F. Monti and S. Myers and T. Nguyen and Javier Rodr{\'i}guez-Pacheco and I. Phillips and M. A. Popecki and K. Rees and Steven A. Rogacki and K. Ruane and Duncan Rust and Mario Salatti and J. A. Sauvaud and Mark Stakhiv and Jason L. Stange and Timothy. J. Stubbs and T. Taylor and Jean-Denis Techer and G{\'e}rard Terrier and R. Thibodeaux and Carlos Fajardo Urdiales and Ali Varsani and Andrew P. Walsh and G. Watson and P. Wheeler and Graham Willis and Robert F. Wimmer–Schweingruber and Berend Winter and Joyce Yardley and Ioannis Zouganelis},
  journal={Astronomy and Astrophysics},
  year={2020},
  volume={642}
}

• C. Owen, R. Bruno, +126 authors I. Zouganelis
• Published 27 August 2020
• Physics
• Astronomy and Astrophysics

The Solar Orbiter mission seeks to make connections between the physical processes occurring at the Sun or in the solar corona and the nature of
the solar wind created by those processes which is subsequently observed at the spacecraft. The mission also targets physical processes occurring
in the solar wind itself during its journey from its source to the spacecraft. To meet the specific mission science goals, Solar Orbiter will be
equipped with both remote-sensing (RS) and in-situ (IS) instruments which will make unprecedented measurements of the solar atmosphere and
the inner heliosphere.
A crucial set of measurements will be provided by the Solar Wind Analyser (SWA) suite of instruments. This suite consists of an Electron Analyser
System (SWA-EAS), a Proton and Alpha particle Sensor (SWA-PAS), and a Heavy Ion Sensor (SWA-HIS) which are jointly served by a central
control and data processing unit (SWA-DPU). Together these sensors will measure and categorise the vast majority of thermal and suprathermal
ions and electrons in the solar wind and determine the abundances and charge states of the heavy ion populations.
The three sensors in the SWA suite are each based on the top hat electrostatic analyser concept, which has been deployed on numerous space
plasma missions. The SWA-EAS uses two such heads, each of which have 360◦
azimuth acceptance angles and ±45◦
aperture deflection plates.
Together these two sensors, which are mounted on the end of the boom, will cover a full sky field-of-view (FoV) (except for blockages by the
spacecraft and its appendages) and measure the full 3D velocity distribution function (VDF) of solar wind electrons in the energy range of a
few eV to ∼ 5 keV. The SWA-PAS instrument also uses an electrostatic analyser with a more confined FoV (-24◦
to +42◦ × ±22.5◦
around the
expected solar wind arrival direction), which nevertheless is capable of measuring the full 3D VDF of the protons and alpha particles arriving at
the instrument in the energy range from 200 eV/q to 20 keV/e. Finally, SWA-HIS measures the composition and 3D VDFs of heavy ions in the
bulk solar wind as well as those of the major constituents in the suprathermal energy range and those of pick-up ions. The sensor resolves the full
3D VDFs of the prominent heavy ions at a resolution of 5 minutes in normal mode and 30 s in burst mode. Additionally, SWA-HIS measures 3D
VDFs of alpha particles at a 4 second resolution in burst mode. Measurements are over a FoV of -33◦
to +66◦ × ±20◦
around the expected solar
wind arrival direction and at energies up to 80 keV/e. The mass resolution (m/∆m) is > 5.
This paper describes how the three SWA scientific sensors, as delivered to the spacecraft, meet or exceed the performance requirements originally
set out to achieve the mission’s science goals. We describe the motivation and specific requirements for each of the three sensors within the SWA
suite, their expected science results, their main characteristics, and their operation through the central SWA-DPU. We describe the combined data
products that we expect to return from the suite and provide to the Solar Orbiter Archive for use in scientific analyses by members of the wider
solar and heliospheric communities. These unique data products will help reveal the nature of the solar wind as a function of both heliocentric
distance and solar latitude. Indeed, SWA-HIS measurements of solar wind composition will be the first such measurements made in the inner
heliosphere. The SWA data are crucial to efforts to link the in situ measurements of the solar wind made at the spacecraft with remote observations
of candidate source regions. This is a novel aspect of the mission which will lead to significant advances in our understanding of the mechanisms
accelerating and heating the solar wind, driving eruptions and other transient phenomena on the Sun, and controlling the injection, acceleration,
and transport of the energetic particles in the heliosphere.