Substorm Observations of Magnetic Perturbations and ULF Waves at Synchronous Orbit by ATS-1 and ATS-6

  • P. J. ColemanJr.
  • R. L. McPherron
Part of the Astrophysics and Space Science Library book series (ASSL, volume 57)


In the empirical study of the geomagnetic cavity, the synchronous equatorial orbit has been shown to be a most advantageous site for scientific measurements. Satellites in this orbit are fixed in the Earth’s main magnetic field so that the records are not dominated by changes due to satellite motion through this field. Also, the satellites traverse the same geometric region of space daily, thus facilitating statistical studies of magnetospheric phenomena. Thirdly, the magnetic field lines leaving the Earth’s surface near the auroral zone cross the equatorial plane close to this orbit, thus subjecting the region to a number of such phenomena.

Previous observations at synchronous orbit with the UCLA fluxgate magnetometers on ATS-1 and ATS-6 have revealed a variety of substorm-associated field variations. These effects may be divided tentatively into two classes, those resulting from instabilities (ULF waves) and those produced by changes in macroscopic current systems. The data and their interpretations will be reviewed in order to illustrate the potential importance of observations in the synchronous orbit during the International Magnetospheric Study.


Magnetic Storm Geomagnetic Activity Dynamic Spectrum Conjugate Point Quiet Time 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. Arthur, C.W. & R.L. McPherron, Observations of 10-45 sec period micropulsations in the morning sector (extended abstract), in Proc. Chapman Mem. Symp. Magnetospheric Motions, 108–112, 1973.Google Scholar
  2. Arthur, C.W. & R.L. McPherron, A preliminary study of simultaneous ground-satel- lite observations of substorm-associated Pi 2 micropulsations and their high frequency enhancement, IGPP Publ. 1266-43, UCLA, 1974a.Google Scholar
  3. Arthur, C.W. & R.L. McPherron, Simultaneous observations of 10-45 sec period waves (abstract), EOS Trans. Am. Geophys. Union 56, 1178 (1974b).Google Scholar
  4. Barfield, J.N. & P.J. Coleman Jr., Storm-related wave phenomena observed at the synchronous equatorial orbit, J. Geophys. Res. 75, 1943–1946 (1970).ADSCrossRefGoogle Scholar
  5. Barfield, J.N.& R.L. McPherron, Statistical characteristics of storm associated Pc 5 micropulsations observed at the synchronous, equatorial orbit, J. Geophys. Res. 77, 4720–4733 (1972a).ADSCrossRefGoogle Scholar
  6. Barfield, J.N. & R.L. McPherron, Investigations of interaction between Pc 1-2 and Pc 5 micropulsations at the synchronous orbit during magnetic storms, J. Geophys. Res. 77, 4707–4719 (1972b).ADSCrossRefGoogle Scholar
  7. Barfield, J.N., R.L. McPherron, P.J. Coleman Jr. & D.J. Southwood, Storm associated Pc 5 micropulsation events observed at the synchronous equatorial orbit, J. Geophys. Res. 77, 143–158 (1972).ADSCrossRefGoogle Scholar
  8. Bossen, M., Substorm-associated Pc 1 micropulsations at ATS 1 and its conjugate point, IGPP Publ. 1418-75, UCLA, 1975.Google Scholar
  9. Bossen, M., R.L. McPherron & C.T. Russell, A statistical study of Pc 1 micropulsations at synchronous orbit, IGPP Publ. 1400-74, UCLA, 1975.Google Scholar
  10. Coleman, P.J. Jr. & W.D. Cummings, Storm time disturbance field at ATS-1, J. Geophys. Res. 76, 51–62(1971).ADSCrossRefGoogle Scholar
  11. Cummings, W.D., R.J. O’Sullivan & P.J. Coleman Jr., Standing Alfven waves in the magnetosphere, J. Geophys. Res. 74, 778–793 (1969).ADSCrossRefGoogle Scholar
  12. Cummings, W.D., P.J. Coleman Jr. & G.L. Siscoe, Quiet day magnetic field at ATS 1, J. Geophys. Res. 76, 926 (1971).ADSCrossRefGoogle Scholar
  13. Heacock, R.R., Two subtypes of Pi micropulsations, J. Geophys. Res. 72, 3905–3917 (1967).ADSCrossRefGoogle Scholar
  14. McPherron, R.L., Correction and analysis of ATS 1 magnetometer data during 1971, IGPP Publ. 995, UCLA, 1971.Google Scholar
  15. McPherron, R.L., Coordinate transformations used in processing ATS 1 magnetic field data, IGPPPubl. 1053, 1973.Google Scholar
  16. McPherron, R.L., Progress report: UCLA fluxgate magnetometer on ATS 6 for the period April 1-September 1, 1974, IGPPPubl. 1388-60, UCLA, 1974.Google Scholar
  17. McPherron, R.L., The quiet time magnetic field at synchronous orbit (extended abstract), EOS Trans. Am. Geophys. Union, 1975.Google Scholar
  18. McPherron, R.L. & P.J. Coleman Jr., Magnetic fluctuations during magnetospheric substorms, 1. Expansion phase, J. Geophys. Res. 75, 3927–3931 (1970).ADSCrossRefGoogle Scholar
  19. McPherron, R.L., C.T. Russell & P.J. Coleman Jr., Comparison of the Olson field model to quiet day magnetic field observations at ATS 1 (extended abstract), in Quantitative Magnetospheric Models, Proc. ESSA Symp., Boulder, Colorado, 1970.Google Scholar
  20. McPherron, R.L., P.J. Coleman Jr. & R.C. Snare, The UCLA fluxgate magnetometer on ATS 6, IEEE Trans. Aerospace Electron. Syst., 1975.Google Scholar
  21. Mead, G.D. & D.H. Fairfield, A quantitative magnetospheric model derived from spacecraft magnetometer data, J. Geophys. Res. 80, 523 (1975).ADSCrossRefGoogle Scholar
  22. Olson, W.P. & W.D. Cummings, Comparison of the predicted and observed magnetic field at ATS 1, J. Geophys. Res. 75, 7117–7121 (1970).ADSCrossRefGoogle Scholar
  23. Olson, W.P. & K.A. Pfitzer, A quantitative model of the magnetospheric magnetic field, J. Geophys. Res. 79, 3739 (1974).ADSCrossRefGoogle Scholar
  24. Subbarao, S., R.L. McPherron & N.E. Cline, Magnetic field depressions at synchronous orbit: A spatial or temporal effect? (extended abstract), in Proc. Chapman Mem. Symp. Magnetospheric Motions, 201–204, 1973.Google Scholar

Copyright information

© D. Reidel Publishing Company, Dordrecht, Holland 1976

Authors and Affiliations

  • P. J. ColemanJr.
    • 1
    • 2
  • R. L. McPherron
    • 1
    • 2
  1. 1.Department of Geophysics and Space PhysicsUniversity of CaliforniaUSA
  2. 2.Institute of Geophysics and Planetary PhysicsUniversity of CaliforniaUSA

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