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Plasma (Total Electron) Density by Radio Techniques

NSSDCA ID: 1977-102A-08

Mission Name: ISEE 1
Principal Investigator:Dr. Christopher C. Harvey


This experiment measured the plasma electron density near the mother satellite and also the total electron content between the mother and the daughter spacecraft. The experiment consisted of two distinct parts. The mother spacecraft carried an experiment (the sounder) to detect resonances of the ambient plasma. After an antenna had been momentarily excited at one of the characteristic frequencies of the plasma in which it was immersed, a pronounced "ringing" was observed. These resonances occurred at the plasma frequency, the upper hybrid resonance, the cyclotron frequency and its harmonics, and the measurement of their frequencies permitted the determination of several plasma parameters, including the electron density. In this experiment, the transmitter was designed to step through 128 sub-bands, covering the characteristic resonance frequencies of the plasma, from 0.3 to 50.9 kHz, and from 0 to 353 kHz. The integrated density between the mother and the daughter was obtained from a second experiment (the propagation experiment) that measured the phase delay introduced by the ambient plasma onto a wave of frequency about 683 kHz transmitted from the mother and received on the daughter (experiment -06). The phase was compared against a phase-coherent signal transmitted from the mother to the daughter by modulation onto a carrier of frequency high enough to be unaffected by the ambient plasma (272.5 MHz). Due to perturbations to other experiments, active operation was on a limited duty cycle.

Alternate Names

  • ISEE1/Plasma_TotalElectron_DensitybyRadioTechniques

Facts in Brief

Mass: 5 kg
Power (avg): 6 W

Funding Agency

  • European Space Agency (International)


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

Additional Information

Questions and comments about this experiment can be directed to: Dr. H. Kent Hills



NameRoleOriginal AffiliationE-mail
Dr. Aubry Michel PetitOther InvestigatorCentre National d'Etudes des Telecommunications
Dr. Roger E. GendrinOther InvestigatorCentre National d'Etudes des Telecommunications
Dr. Jacquelyne M. EtchetoOther InvestigatorCentre National d'Etudes des
Dr. John R. McAfeeOther InvestigatorNOAA Environmental Research Laboratories
Dr. Rejean J. L. GrardOther InvestigatorESA-European Space Research and Technology
Dr. Dyfrig JonesOther InvestigatorBritish Antarctic Survey
Dr. Christopher C. HarveyPrincipal InvestigatorObservatoire de Paris,

Selected References

  • Harvey, C. C., et al., ISEE electron density experiment, IEEE Trans. Geosci. Electron., GE-16, No. 3, 231-238, doi:10.1109/TGE.1978.294553, July 1978.
  • Harvey, C. C., et al., Early results from the ISEE electron density experiment, Space Sci. Rev., 23, No. 1, 39-58, doi:10.1007/BF00174110, Mar. 1979.
  • Harvey, C. C., Anomalous behavior of ISEE-1 detected by the electron density experiment, Proc. of the 17th ESLAB Symp. on 'Spacecraft/Plasma Interactions and Their Influence on Field and Particle Measurements', Noordwijk, The Netherlands, Sept. 13-16, 1983, 41-46, ESA SP-198, Dec. 1983.
  • Lacombe, C., et al., Electron plasma waves upstream of the earth's bow shock, J. Geophys. Res., 90, No. A1, 73-94, doi:10.1029/JA090iA01p00073, Jan. 1985.
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