BackForwardInstrument:  SEI 

Instrument details
Acronym SEI
Full name Suprathermal Electron Imager
Purpose To measure the 2-D energy and angular distributions of thermal electrons and soft electrons
Short description Hemispherical electron analyzer with electron amplification producing images on a phosphor screen. The images are optically coupled to a 256x256 CCD device. Measurements are made in the range 1-200 eV/q with particular emphasis on photoelectrons in the 1-50 eV range, which are believed to play an important role in the polar wind outflow
Background Part of a package of instruments to study the Magnetosphere
Scanning Technique Travelling cross the Magnetosphere in an elliptical orbit
Resolution N/A
Coverage / Cycle Lower magnetosphere, daily
Mass Power Data Rate


Providing Agency CSA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2014 to 2021
Last update: 2021-10-02
Detailed characteristics
Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Instrument classification
  • Solar and space environment monitors
  • Energetic particle spectrometer
WIGOS Subcomponents
  • Subcomponent 2
  • Magnetospheric energetic particles and magnetometers
  • Electron sensor [cross magnetosphere]
Mission objectives
Primary mission objectives
  • Electron differential directional flux
Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
Note: * Primary mission objective.
VariableRelevance for measuring this variableOperational limitationsExplanation
Electron differential directional flux*2 - very highNo specific limitation.Magnetosphere, low energy (up to 40 keV)