Solar Wind Electrons Alphas and Protons (SWEAP) Investigation: Design of the Solar Wind and Coronal Plasma Instrument Suite for Solar Probe Plus

Justin C. Kasper, Robert Abiad, Gerry Austin, Marianne Balat-Pichelin, Stuart D. Bale, John W. Belcher, Peter Berg, Henry Bergner, Matthieu Berthomier, Jay Bookbinder, Etienne Brodu, David Caldwell, Anthony W. Case, Benjamin D.G. Chandran, Peter Cheimets, Jonathan W. Cirtain, Steven R. Cranmer, David W. Curtis, Peter Daigneau, Greg DaltonBrahmananda Dasgupta, David DeTomaso, Millan Diaz-Aguado, Blagoje Djordjevic, Bill Donaskowski, Michael Effinger, Vladimir Florinski, Nichola Fox, Mark Freeman, Dennis Gallagher, S. Peter Gary, Tom Gauron, Richard Gates, Melvin Goldstein, Leon Golub, Dorothy A. Gordon, Reid Gurnee, Giora Guth, Jasper Halekas, Ken Hatch, Jacob Heerikuisen, George Ho, Qiang Hu, Greg Johnson, Steven P. Jordan, Kelly E. Korreck, Davin Larson, Alan J. Lazarus, Gang Li, Roberto Livi, Michael Ludlam, Milan Maksimovic, James P. McFadden, William Marchant, Bennet A. Maruca, David J. McComas, Luciana Messina, Tony Mercer, Sang Park, Andrew M. Peddie, Nikolai Pogorelov, Matthew J. Reinhart, John D. Richardson, Miles Robinson, Irene Rosen, Ruth M. Skoug, Amanda Slagle, John T. Steinberg, Michael L. Stevens, Adam Szabo, Ellen R. Taylor, Chris Tiu, Paul Turin, Marco Velli, Gary Webb, Phyllis Whittlesey, Ken Wright, S. T. Wu, Gary Zank

Research output: Contribution to journalReview articlepeer-review

462 Scopus citations


The Solar Wind Electrons Alphas and Protons (SWEAP) Investigation on Solar Probe Plus is a four sensor instrument suite that provides complete measurements of the electrons and ionized helium and hydrogen that constitute the bulk of solar wind and coronal plasma. SWEAP consists of the Solar Probe Cup (SPC) and the Solar Probe Analyzers (SPAN). SPC is a Faraday Cup that looks directly at the Sun and measures ion and electron fluxes and flow angles as a function of energy. SPAN consists of an ion and electron electrostatic analyzer (ESA) on the ram side of SPP (SPAN-A) and an electron ESA on the anti-ram side (SPAN-B). The SPAN-A ion ESA has a time of flight section that enables it to sort particles by their mass/charge ratio, permitting differentiation of ion species. SPAN-A and -B are rotated relative to one another so their broad fields of view combine like the seams on a baseball to view the entire sky except for the region obscured by the heat shield and covered by SPC. Observations by SPC and SPAN produce the combined field of view and measurement capabilities required to fulfill the science objectives of SWEAP and Solar Probe Plus. SWEAP measurements, in concert with magnetic and electric fields, energetic particles, and white light contextual imaging will enable discovery and understanding of solar wind acceleration and formation, coronal and solar wind heating, and particle acceleration in the inner heliosphere of the solar system. SPC and SPAN are managed by the SWEAP Electronics Module (SWEM), which distributes power, formats onboard data products, and serves as a single electrical interface to the spacecraft. SWEAP data products include ion and electron velocity distribution functions with high energy and angular resolution. Full resolution data are stored within the SWEM, enabling high resolution observations of structures such as shocks, reconnection events, and other transient structures to be selected for download after the fact. This paper describes the implementation of the SWEAP Investigation, the driving requirements for the suite, expected performance of the instruments, and planned data products, as of mission preliminary design review.

Original languageEnglish (US)
Pages (from-to)131-186
Number of pages56
JournalSpace Science Reviews
Issue number1-4
StatePublished - Dec 1 2016
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Acceleration
  • Corona
  • Heating
  • Solar probe plus
  • Solar wind plasma


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