BackForwardInstrument:  PWI (Polar) 

Instrument details
Acronym PWI (Polar)
Full name Plasma Wave Instrument
Purpose To study wave/particle processes mediated by electromagnetic turbulence (momentum transfer in the geospace system, particularly in the boundaries)
Short description Assemblage of several sensors for detecting the electric and magnetic fields of plasma waves: 1) a pair of orthogonal two-sphere electric antennas; 2) a short two-sphere electric antenna aligned along the spacecraft spin axis; 3) a triaxial magnetic search coil; and 4) a magnetic loop antenna. Magnetic and electric field oscillations in the range 0.0001-800 kHz
Background Part of a package of instruments to explore the Magnetosphere
Scanning Technique Travelling cross the Magnetosphere in a highly-elliptical orbit
Resolution N/A
Coverage / Cycle Large fraction of magnetosphere and ionosphere
Mass Power Data Rate


Providing Agency NASA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 1996 to 2008-04-15
Last update: 2017-04-13
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
  • Field or radiowave sensor
WIGOS Subcomponents No WIGOS subcomponents have been defined.
Mission objectives
Primary mission objectives
  • Electron Density
  • Ionospheric plasma density
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
Geomagnetic field5 - marginalNo specific limitation.Magnetic field measured through observation of oscillations of the electric fileld
Electric Field2 - very highNo specific limitation.Electric field measured by magnetic and electric field oscillations
Ionospheric plasma density*1 - primaryNo specific limitation.Ionospheric plasma density measured through observation of oscillations of the magnetic and electric fields
Electron Density*2 - very highAssimilation in gravity model needed.. No specific limitation.Electron density measured through observation of oscillations of the magnetic and electric fields