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Swarm: A constellation to study the Earth’s magnetic field


The Swarm mission was selected as the 5th mission in ESA’s Earth Explorer Programme in 2004. The mission will provide the best ever survey of the geomagnetic field and its temporal evolution that will lead to new insights into the Earth system by improving our understanding of the Earth’s interior and its effect on Geospace, the vast region around the Earth where electrodynamic processes are influenced by the Earth’s magnetic field. Scheduled for launch in 2010, the mission will comprise a constellation of three satellites, with two spacecraft flying sideby- side at lower altitude (450 km initial altitude), thereby measuring the East-West gradient of the magnetic field, and the third one flying at higher altitude (530 km). High-precision and high-resolution measurements of the strength, direction and variation of the magnetic field, complemented by precise navigation, accelerometer and electric field measurements, will provide the necessary observations that are required to separate and model the various sources of the geomagnetic field. This results in a unique “view” inside the Earth from space to study the composition and processes of its interior. It also allows analysing the Sun’s influence within the Earth system. In addition practical applications in many different areas, such as space weather, radiation hazards, navigation and resource management, will benefit from the Swarm concept.


  1. Alexandrescu, M., D. Gibert, G. Hulot, J. L. Le Mouël, and G. Saracco, Worldwide wavelet analysis of geomagnetic jerks, J. Geophys. Res., 101, 21975–21994, 1996.

  2. Amit, H. and P. Olson, Helical core flow from geomagnetic secular variation, Phys. Earth Planet Inter., 147, 1–25, 2004.

  3. Bijwaard, H. and W. Spakman, Non-linear global P-wave tomography by iterated linearized inversion, Geophys. J. Int., 110, 251–266, 2000.

  4. Bloxham, J. and A. Jackson, Time-dependent mapping of the magnetic field at the core-mantle boundary, J. Geophys. Res., 97, 19537–19568, 1992.

  5. Bloxham, J., S. Zatman, and M. Dumberry, The origin of geomagnetic jerks, Nature, 420, 65–68, 2002.

  6. Constable, S. and C. Constable, Observing geomagnetic induction in magnetic satellite measurements and associated implications for mantle conductivity, Geochem. Geophys. Geosys., 5(1), Q01006 doi:10.1029/ 2003GC000634, 2004.

  7. Dormy, E. and M. Mandea, Tracking geomagnetic impulses at the core-mantle boundary, Earth Planet. Sci. Lett., 237, 300–309, 2005.

  8. Editors of Science, Areas to watch in 2003, “A sun-climate connection”, Science, 298, 2298, 2002.

  9. ESA SP-1279-6, The Earth’s Magnetic Field and Environment Explorers, ESA Publication Division, ESTEC., Noordwijk, 2004. Technical and Programmatic Annex to ESA SP-1279-6, The Earth’s Magnetic Field and Environment Explorers, ESA Publication Division, ESTEC., Noordwijk, 2004.

  10. Eymin, C. and G. Hulot, On core surface flows inferred from satellite magnetic data, Phys. Earth Planet. Int, 152, 200–220, 2005.

  11. Finlay, C. and A. Jackson, Equatorially dominated magnetic field change at the surface of earth’s core, Science, 300, 2084–2086, 2003.

  12. Fox Maule, C., M. Purucker, N. Olsen, and K. Mosegaard, Heat Flux Anomalies in Antarctica Revealed by Satellite Magnetic Data, Science, 309, 464–467, doi:10.1126/science.1106888, 2005.

  13. Friis-Christensen E., H. Lühr, and G. Hulot: Swarm—a constellation to study the dynamics of the Earth’s magnetic field and its interaction with the Earth system, Proposal for ESA Earth Explorer Opportunity Missions, January 2002, ISSN 1602-527X, DSRI Report 1/2002, 2002.

  14. Holme, R., Electromagnetic core-mantle coupling III. Laterally varying mantle conductance, Phys. Earth Planet Inter, 117, 329–344, 2000.

  15. Holme, R. and O. de Viron, Geomagnetic jerks and a high-resolution length-of-day profile for core studies, Geophys. J. Int., 160, 435–439, 2005.

  16. Hulot, G. and A. Chulliat, On the possibility of quantifying diffusion and horizontal Lorentz forces at the Earth’s core surface, Phys. Earth Planet Inter., 135, 47–54, 2003.

  17. Hulot, G., C. Eymin, B. Langlais, M. Mandea, and N. Olsen, Small-scale structure of the Geodynamo inferred from Oersted and Magsat satellite data, Nature, 416, 620–623, 2002.

  18. Jackson, A., Time-dependency of tangentially geostrophic core surface motions, Phys. Earth Planet Inter., 103, 293-311, 1997.

  19. Jackson, A., A. Jonkers, and M. Walker, Four centuries of geomagnetic secular variation from historical records, Phil. Trans. R. Soc. Lond., 358, 957–990, 2000.

  20. Jault, D., Electromagnetic and topographic coupling, and LOD variations, in edited by C. A. Jones and K. Zhang (Eds), “Earth’s core and lower mantle”, The Fluid Mechanics of Astrophysics and Geophysics, Taylor and Francis, London, pp. 56–76, 2003.

  21. Kuvshinov, A., T. J. Sabaka, and N. Olsen, 3-D electromagnetic induction studies using the Swarm constellation: Mapping conductivity anomalies in the Earth’s mantle, Earth Planets Space, 58, this issue, 417–427, 2006.

  22. Langel, R., G. Ousley, and J. Berbert, The Magsat Mission, Geophys. Res. Lett., 9, 243–245, 1982.

  23. Le Huy, M., M. Mandea, J. L. Le Mouël, and A. Pais, Time evolution of the fluid at the top of the core. Geomagnetic jerks, Earth Planets Space, 52, 163–173, 2000.

  24. Lesur, V., S. Macmillan, and A. Thomson, Deriving main field and secular variation models from synthetic Swarm satellite and observatory data, Earth Planets Space, 58, this issue, 409–416, 2006.

  25. Liu, H. and H. Lühr, Strong disturbance of the upper thermosphere density due to magnetic storms: CHAMP observations, J. Geophys. Res., 110, A04301; doi:10.1029/2004JA010741, 2005.

  26. Liu, H., H. Lühr, V. Henize, and W. Köhler, Global distribution of the thermospheric total mass density derived from CHAMP, J. Geophys. Res., 110, A04301; doi:10.1029/2004JA010741, 2005.

  27. Lühr, H., M. Rother, S. Maus, W. Mai, and D. Cooke, The diamagnetic effect of the equatorial Appleton anomaly: Its characteristics and impact on geomagnetic field modelling, Geophys. Res. Lett., 30, 17, 1906, doi:10.1029/2003GL017407, 2003.

  28. Lühr, H., M. Rother, W. Köhler, P. Ritter, and L. Grunwaldt, Thermospheric up-welling in the cusp region, evidence from CHAMP observations, Geophys. Res. Lett., 31, L06805, doi:10.1029/2003GL019314, 2004.

  29. Mandea Alexandrescu, M., D. Gibert, J.-L. Le Mouël, G. Hulot, and G. Saracco, An estimate of average lower mantle conductivity by wavelet analysis of geomagnetic jerks, J. Geophys. Res, 104, 17735–17745, 1999.

  30. Mandea, M., E. Bellanger, and J. L. Le Mouël, A geomagnetic jerk for the end of the 20th century?, Earth planet. Sci. Lett., 183, 369–373, 2000.

  31. Manoj, C., A. Kuvshinov, S. Maus, and H. Lühr, Ocean circulation generated magnetic signals, Earth Planets Space, 58, this issue, 429–437, 2006.

  32. Marsh, N. and H. Svensmark, Low cloud properties influenced by cosmic rays, Phys. Rev. Lett., 85, 5004–5007, 2000.

  33. Maus, S. and H. Lühr, Signature of the quiet-time magnetospheric magnetic field and its electromagnetic induction, Geophys. J. Int., doi:10:1111/j.1365-246X.2005.02691.x, 2005.

  34. Maus, S., H. Lühr, G. Balaris, M. Rother, and M. Mandea, Introducing POMME, the Potsdam Magnetic Model of the Earth, in Earth Observation with CHAMP, Results from Three Years in Orbit, edited by C. Reigberg, H. Lühr, P. Schwintzer, J. Wickert, Springer, Berlin, pp. 293–298, 2005.

  35. Maus, S., M. Rother, K. Hemant, C. Stolle, H. Lühr, A. Kuvshinov, and N. Olsen, Earth’s crustal magnetic field determined to spherical harmonic degree 90 from CHAMP satellite measurements, Geophys. J. Int., doi: 10.1111/j.1365-246X.2005.02833.x, 2006a.

  36. Maus, S., H. Lühr, and M. Purucker, Simulation of the high-degree litho-spheric field recovery for the Swarm constellation of satellites, Earth Planets Space, 58, this issue, 397–407, 2006b.

  37. Moretto, T., S. Vennerstrøm, N. Olsen, L. Raststätter, and J. Raeder, Using global magnetospheric models for simulation and interpretation of Swarm external field measurements, Earth Planets Space, 58, this issue, 439–449, 2006.

  38. Neubert, T., M. Mandea, G. Hulot, R. von Frese, F. Primdahl, J. L. Jørgensen, E. Friis-Christensen, P. Stauning, N. Olsen, and T. Risbo, Ørsted satellite captures high-precision geomagnetic field data, EOS Transactions, AGU, 82(7), 81–88, 2001.

  39. Olsen, N., Induction studies with satellite data, Surveys in Geophysics, 20, 309–340, 1999.

  40. Olsen, N., T. J. Sabaka, and F. Lowes, New parameterization of external and induced fields in geomagnetic field modeling, and a candidate model for IGRF, Earth Planets Space, 57, 1141–1149, 2005.

  41. Olsen, N., H. Lühr, T. J. Sabaka, M. Mandea, M. Rother, L. Tøffner-Clausen, and S. Choi, CHAOS—A model of Earths magnetic field derived from CHAMP, Ørsted and SAC-C magnetic satellite data, Geophys. J. Int., doi: 10.1111/j.1365-246X.2005.(in press), 2006.

  42. Olsen, N., R. Haagmans, T. J. Sabaka, A. Kuvshinov, S. Maus, M. E. Purucker, M. Rother, V. Lesur, and M. Mandea, The Swarm End-to-End mission simulator study: A demonstration of separating the various contributions to Earth’s magnetic field using synthetic data, Earth Planets Space, 58, this issue, 359–370, 2006a.

  43. Pais, A. and G. Hulot, Length of day decade variations, torsional oscillations and inner core superrotation: evidence from recovered core surface zonal flows, Phys. Earth Planet Inter, 118, 291–316, 2000.

  44. Pais, M. A., O. Oliveira, and F. Nogueira, Nonuniqueness of inverted core-mantle boundary flows and deviations from tangential geostrophy, J. Geophys. Res, 109, B08105, doi:10.1029/2004JB003012, 2004.

  45. Purucker, M., B. Langlais, N. Olsen, G. Hulot, and M. Mandea, The southern edge of cratonic North America: Evidence from new satellite magnetometer observations, Geophys. Res. Lett., 29(15), ORS1, 2002a.

  46. Purucker, M., H. McCreadie, S. Vennerstroem, G. Hulot, N. Olsen, H. Luehr, and E. Garnero, Highlights from AGU’s virtual session on new magnetic field satellites, EOS, 83, 368, 2002b.

  47. Reigber, C., H. Lühr, and P. Schwintzer, CHAMP mission status, Adv. Space Res., 30, 129–134, 2002.

  48. Ritter, P. and H. Lühr, Curl-B technique applied to Swarm constellation for determining field-aligned currents, Earth Planets Space, 58, this issue, 463–476, 2006.

  49. Sabaka, T. J. and N. Olsen, Enhancing comprehensive inversions using the Swarm constellation, Earth Planets Space, 58, this issue, 371–395, 2006.

  50. Sabaka, T. J., N. Olsen, and M. Purucker, Extending comprehensive models of the Earth’s magnetic field with Ørsted and CHAMP, Geophys. J. Int., 159(2), 521–547, 2004.

  51. Tyler, R. H., S. Maus, and H. Lühr, Satellite observations of magnetic fields due to ocean tidal flow, Science, 299, 239–241, 2003.

  52. Vennerstrom, S., T. Moretto, L. Raststätter, and J. Raeder, Modeling and analysis of solar wind generated contributions to the near-Earth magnetic field, Earth Planets Space, 58, this issue, 451–461, 2006.

  53. Yu, F. and R. P. Turco, From molecular clusters to nanoparticles: Role of ambient ionisation in tropospheric aerosol formation, J. Geophys. Res., 106, 4797–4814, 2001.

  54. Zatman, S. and J. Bloxham, Torsional oscillations and the magnetic field within the Earth’s core, Nature, 388, 760–763, 1997.

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Correspondence to E. Friis-Christensen.

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Friis-Christensen, E., Lühr, H. & Hulot, G. Swarm: A constellation to study the Earth’s magnetic field. Earth Planet Sp 58, 351–358 (2006).

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Key words

  • Geomagnetism
  • magnetic field mission
  • Swarm satellites