Skip to main content
Log in

The Freja science mission

  • Published:
Space Science Reviews Aims and scope Submit manuscript

Abstract

Freja *, a joint Swedish and German scientific satellite launched on october 6 1992, is designed to give high temporal/spatial resolution measurements of auroral plasma characteristics. A high telemetry rate (520 kbits s−1) and ≈15 Mbyte distributed on board memories that give on the average 2 Mbits s−1 for one minute enablesFreja to resolve meso and micro scale phenomena in the 100 m range for particles and 1–10 m range for electric and magnetic fields. The on-board UV imager resolve auroral structures of kilometer size with a time resolution of one image per 6 s. Novel plasma instruments giveFreja the capability to increase the spatial/temporal resolution orders of magnitudes above that achieved on satellites before. The scientific objective ofFreja is to study the interaction between the hot magnetospheric plasma with the topside atmosphere/ionosphere. This interaction leads to a strong energization of magnetospheric and ionospheric plasma and an associated erosion, and loss, of matter from the Terrestrial exosphere.Freja orbits with an altitude of ≈600–1750 km, thus covering the lower part of the auroral acceleration region. This altitude range hosts processes that heat and energize the ionospheric plasma above the auroral zone, leading to the escape of ionospheric plasma and the formation of large density cavities.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  • Albert, R. D.: 1967, ‘Nearly Monoenergetic Electron Fluxes Detected During a Visible Aurora’,Phys. Rev. Letters 18, 369–372.

    Google Scholar 

  • Alfvén, H.: 1958, ‘On the Theory of Magnetic Storms and Aurorae’,Tellus 10, 104.

    Google Scholar 

  • Alfvén, H.: 1981,Cosmic Plasma, D. Reidel Publ. Co., Dordrecht, Holland.

    Google Scholar 

  • André, M. and Eliasson, L.: 191992, ‘Electron Acceleration by Low-Frequency Electric Field Fluctuations: Electron Conics’,Geophys. Res. Letters 19, 1073.

    Google Scholar 

  • Bahnsen, A., Pedersen, M. B., Jespersen, M., Ungstrup, E., Eliasson, L., Murphree, L. S., Elphinstone, R. D., Blomberg, L., Holmgren, G., and Zanetti, L. J.: 1989, ‘Viking Observations at the Source Region of Auroral Kilometric Radiation’,J. Geophys. Res. 94, 6643.

    Google Scholar 

  • Benson, R. F. and Calvert, W.: 1979, ‘ISIS 1 Observations of the Source of Auroral Kilometric Radiation’,Geophys. Res. Letters 6, 479–482.

    Google Scholar 

  • Calvert, W.: 1981, ‘The Auroral Plasma Cavity’,Geophys. Res. Letters 8, 919–922.

    Google Scholar 

  • Chang, T. and Coppi, B.: 1981, ‘Lower Hybrid Acceleration and Ion Evolution in the Suprauroral Region’,Geophys. Res. Letters 8, 1253.

    Google Scholar 

  • Chappell, C. R., Moore, T. E., and Wiate, J. H. Jr.: 1987, ‘The Ionosphere as a Fully Adequate Source of Plasma for the Earth's Magnetosphere’,J. Geophys. Res. 92, 5896.

    Google Scholar 

  • Chiu, Y. T. and Schulz, M.: 1978, ‘Self-Consistent Particle and Parallel Electrostatic Field Distribution in the Magnetospheric-Ionospheric Auroral Region’,J. Geophys. Res. 83, 629.

    Google Scholar 

  • Evans, D. S.: 1968, ‘The Observations of a Near Monoenergetic Flux of Auroral Electrons’,J. Geophys. Res. 73, 2315.

    Google Scholar 

  • Evans, D. S.: 1974, ‘Precipitating Electron Fluxes Formed by a Magnetic Field Aligned Potential Difference’,J. Geophys. Res. 79, 2853.

    Google Scholar 

  • Frank, L. A. and Ackerson, K. L.: 1971, ‘Observations of Charged Particle Precipitation into the Auroral Zone’,J. Geophys. Res. 76, 3612.

    Google Scholar 

  • Fälthammar, C.-G.: 1983, ‘Magnetic-Field-Aligned Electric Fields’,ESA Journal 7, 385.

    Google Scholar 

  • Goertz, C. K. and Boswell, R. W.: 19798, ‘Magnetosphere-Ionosphere Coupling’,J. Geophys. Res. 84, 7239.

  • Gurnett, D. A. and Frank, L. A.: 1973, ‘Observed Relationship between Electric Field and Auroral Particle Precipitation’,J. Geophys. Res. 78, 145.

    Google Scholar 

  • Harrendel, G.: 1980, ‘Auroral Particle Acceleration — An Example of a Universal Plasma Process’,ESA Journal 4, 197.

    Google Scholar 

  • Haerendel, G.: 1989, ‘Cosmic Linear Accelerators’,Proc. of the International School and Workshop on Plasma Astrophysics, ESA SP-285, ESA, Noordwijk, pp. 37–44.

  • Hoffman, R. A. and Evans, D. S.: 1968, ‘Field-Aligned Electron Bursts at High Latitude Observed by OGO-4’,J. Geophys. Res. 73, 6201.

    Google Scholar 

  • Hultqvist, B.: 1988, ‘On the Acceleration of Electrons and Positive Ions in the Same Direction Along Magnetic Field Lines by Parallel Electric Fields’,J. Geophys. Res. 93, 9777.

    Google Scholar 

  • Ijima, T. and Potemra, T. A.: 1978, ‘Large-Scale Characteristics of Field Aligned Currents Associated with Substorms’,J. Geophys. Res. 83, 559.

    Google Scholar 

  • Klumpar, D. M.: 1973, ‘Parallel Electric Fields’,Planetary Space Sci. 21, 741.

    Google Scholar 

  • Lennartson, W.: 1976, ‘On the Magnetic Mirroring as the Basic Cause of Parallel Electric Fields’,J. Geophys. Res. 81, 5583.

    Google Scholar 

  • Lennartson, W.: 1980, ‘On the Consequences of the Interaction between the Auroral Plasma and the Geomagnetic Field’,Planetary Space Sci. 28, 135.

    Google Scholar 

  • Lundin, R. and Hultqvist, B.: 1989, ‘Ionospheric Plasma Escape by High-Altitude Electric Fields: Magnetic Moment Pumping’,J. Geophys. Res. 94, 6665–6680.

    Google Scholar 

  • Lundin, R. and Sandahl, I.: 1978,Some Characteristics of the Parallel Electric Field Acceleration of Electrons over Discrete Auroral Arcs as Observed from Two Rocket Flights,ESA SP-135, 125.

  • Lundin, R., Gustafsson, G., Eriksson, A. I., and Marklund, G.: 1990, ‘On the Importance of High-Altitude Low-Frequence Electric Fluctuations for the Escape of Ionospheric Ions’,J. Geophys. Res. 95, 5905.

    Google Scholar 

  • Lyons, L. R., Evans, D. S., and Lundin, R.: 1979, ‘An Observed Relation between Magnetic Field Aligned Electric Fields and Downward Electron Fluxes in the Vicinity of Auroral Forms’,J. Geophys. Res. 84, 457.

    Google Scholar 

  • Lysak, R. L. and Dum, C. T.: 1983, ‘Dynamics of Magnetospheric-Ionospheric Coupling Including Turbulent Transport’,J. Geophys. Res. 88, 365.

    Google Scholar 

  • Lysak, R. L., Hudson, M. K., and Temerin, M.: 1980, ‘Ion Heating by Strong Electrostatic Ion Cyclotron Turbulence’,J. Geophys. Res. 85, 678.

    Google Scholar 

  • McFadden, J. P., Carlson, C. W., Boehm, M. H., and Hallinan, T. J.: 1987, ‘Field-Aligned Electron Flux Oscillations that Produce Flickering Aurora’,J. Geophys. Res. 92, 11133.

    Google Scholar 

  • McFadden, J. P., Carlson, C. W., and Boehm, M.: 1990, ‘Structure of an Energetic Narrow Discrete Arc’,J. Geophys. Res. 95, 6533–6547.

    Google Scholar 

  • McIlwain, C. E.: 1960, ‘Direct Measurement of Particles Producing Visible Aurora’,J. Geophys. Res. 65, 2727.

    Google Scholar 

  • Menietti, J. D. and Burch, J. L.: 1985, ‘“Electron Conic” Signatures Observed in the Nightside Auroral Zone and Over the Polar Cap’,J. Geophys. Res. 90, 5345.

    Google Scholar 

  • Mizera, P. J. and Fennell, J. F.: 1977, ‘Signatures of Electric Fields from High and Low Altitude Particle Distributions’,Geophys. Res. Letters 4, 311.

    Google Scholar 

  • Mozer, F. S., Carlson, C. W., Hudson, M. K., Torbert, R. B., Parady, B., Yatteau, J., and Kelley, M. C.: 1977, ‘Observations of Paired Electrostatic Shocks in the Polar Magnetosphere’,Phys. Rev. Letters 38, 292.

    Google Scholar 

  • Papadopoulos, K. and Coffey, T.: 1974, ‘Anomalous Resistivity of the Auroral Plasma’,J. Geophys. Res. 79, 1558.

    Google Scholar 

  • Reiff, P. H., Collin, H. L., Craven, J. D., Burch, J. L., Winningham, J. D., Shelley, E. G., Frank, L. A., and Friedman, M. A.: 1988, ‘Determination of Auroral Electrostatic Potentials Using High- and Low-Altitude Particle Distributions’,J. Geophys. Res. 93, 7441.

    Google Scholar 

  • Shelley, E. G., Johnson, R. G., and Sharp, R. D.: 1976, ‘Satellite Observations of an Ionospheric Acceleration Mechanism’,Geophys. Res. Letters 3, 654.

    Google Scholar 

  • Temerin, M., Cerny, K., Lotko, W., and Mozer, F. S.: 1982, ‘Observations of Double Layers and Solitary Waves in Auroral Plasma’,Phys. Rev. Letters 48, 1175.

    Google Scholar 

  • Thelin, B. and Lundin, R.: 1990, ‘Upflowing Ionospheric Ions and Electrons in the Cusp-Cleft Region’,J. Geomag. Geoelectr. 42, 753.

    Google Scholar 

  • Ungstrup, E., Klumpar, D. M., and Heikkila, W. J.: 1979, ‘Low Altitude Acceleration of Ionospheric Ions’,J. Geophys. Res. 84, 4289.

    Google Scholar 

  • Vago, J. L., Kintner, P. M., Chesney, S. W., Arnoldy, R. L., Lynch, K. A., Moore, T. E., and Pollock, C. J.: 1992, ‘Transverse Ion Acceleration by Localized Lower Hybrid Waves in the Topside Auroral Ionosphere’,J. Geophys. Res. 97, 16935–16975.

    Google Scholar 

  • Whalen, B. A., Bernstein, W., and Daley, P. W.: 1978, ‘Low Altitude Acceleration of Ionospheric Ions’,Geophys. Res. Letters 5, 55.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Lundin, R., Haerendel, G. & Grahn, S. The Freja science mission. Space Sci Rev 70, 405–419 (1994). https://doi.org/10.1007/BF00756879

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00756879

Keywords

Navigation