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Three dimensional plasma analyzer (3DA)

NSSDCA ID: 1997-075B-03

Mission Name: Equator-S
Principal Investigator:Prof. George K. Parks


The instrument consists of an electron electrostatic analyzer (EESA) and an ion electrostatic analyzer (PESA). The analyzer is a symmetrical spherical-section electrostatic analyzer (top-hat design) with a disc-shaped field of view (FOV) of 180 degrees directed perpendicular to the spacecraft body. The complete solid-angle sphere is thus covered in one spin period of 1.5 seconds. The analyzers measure electron and ion distribution functions in 192 angle- and 56 energy-channels, in the energy-per-charge range 10 eV - 25 keV. Moments of the distributions are computed on board. The 3DA instrument (together with the EPI instrument) is a derivative of the 3D Plasma and Energetic Particle Instrument on the WIND spacecraft.

Alternate Names

  • 3DA
  • Equator-S/3DA

Facts in Brief

Mass: 8.6 kg
Power (avg): 7.1 W


  • Space Physics: Magnetospheric Studies
  • Space Physics: Heliospheric Studies

Additional Information

Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Prof. George K. ParksLead InvestigatorUniversity of
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