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Hot Plasma Experiment (HPE)

NSSDCA ID: 1992-064A-03

Mission Name: Freja
Principal Investigator:Dr. Lars Eliasson


The apparatus consisted of an electron spectrometer (MATE) and an ion composition spectrometer (TICS), each feeding into a DPU. The electron spectrometer is a magnetic imaging spectrometer of 120 deg field of view. The 16 energy bands had width of 15-30% at any energy and covered the range of 0.1 keV-120 keV. Pitch angle information was obtained from incidence through 25 angular sectors in the spin plane. TICS was a spherical plate electrostatic analyzer of energy; the ions were then accelerated by a chosen voltage (0, 300,2800, or 4000 V) before entering a mass spectrometer. Structured position sensitive detectors enabled determination of both mass and direction of each ion. The overall energy range was 0.5-15000 E/q, and was covered in 32 bands. TICS was aimed in the direction of the spin axis, and could discriminate among 30 angular sectors. Data from each instrument were preprocessed by the DPU before telemetering or storing. 100 complete energy-direction (16 energies, 25 directions) matrices per second for electrons were obtained. Also obtained were 100 mass-direction (40 masses, 30 directions) matrices per second, at any energy band. The instrument is only partly operational since late 1995.

Alternate Names

  • Freja/HPE
  • HPE

Facts in Brief

Mass: 6.39 kg
Power (avg): 7.5 W
Bit rate (avg): 20 kbps

Funding Agency

  • Unknown (Sweden)


  • Space Physics: Ionospheric Studies
  • Space Physics: Magnetospheric Studies

Additional Information

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



NameRoleOriginal AffiliationE-mail
Dr. Charles W. CarlsonCo-InvestigatorUniversity of California,
Dr. James A. KoehlerCo-InvestigatorUniversity of
Dr. Gerhard HaerendelCo-InvestigatorMax-Planck-Institut fur Extraterrestrische
Dr. Donald J. McEwenCo-InvestigatorUniversity of
Dr. B. A. WhalenCo-InvestigatorNational Research Council of Canada
Dr. Bengt K.G. HultqvistCo-InvestigatorSwedish Institute for Space
Dr. Goetz PaschmannCo-InvestigatorMax-Planck-Institut fur Extraterrestrische
Dr. Hans BorgCo-InvestigatorSwedish Institute for Space
Dr. Gerhard KremserCo-InvestigatorMax-Planck-Institut fur Aeronomie
Dr. David S. HallCo-InvestigatorRutherford Appleton
Dr. Risto J. PellinenCo-InvestigatorFinnish Meteorological
Prof. Rickard LundinCo-InvestigatorSwedish Institute for Space
Dr. Hannu KoskinenCo-InvestigatorFinnish Meteorological
Dr. Ingrid SandahlCo-InvestigatorSwedish Institute for Space
Mr. Mats AndreCo-InvestigatorSwedish Institute for Space Physics
Mr. Olle NorbergCo-InvestigatorSwedish Institute for Space
Dr. Lars EliassonPrincipal InvestigatorSwedish Institute for Space
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