Accession Number:



Study of Magnetospheric Currents and Resultant Surface Magnetic Variations.

Descriptive Note:

Final rept. 1 Oct 76-1 Feb 80,

Corporate Author:


Report Date:


Pagination or Media Count:



We have completed computer simulations of the inner magnetosphere, for the substorm-type event of 19 September 1976. Several computer runs have been performed, with various sets of input parameters. Data from the Air Force S3-2 satellite and ground magnetometers were used for model inputs. Model predictions were analyzed and exhaustively compared with data from the S3-2 satellite, the AFGL magnetometer chain and many other sources. Agreement between theory and data was very satisfactory in most respects. The model injected a realistic ring current during the substorm. Many features of various types of observations were correctly predicted by the model, which was then used to suggest physical interpretations of the features. The predicted latitudinal distribution of region-2 Birkeland currents disagrees with S3-2 observations in a way that appears to be independent of details of the model, input inaccuracies, etc. Some implications of this discrepancy for the theory of the plasma sheet and magnetospheric substorms have been worked out. The computed total Joule heating rate in our modeling region is larger than would be estimated by a standard method, and the time-integrated Joule heating rate is about twice the change in model ring-current energy. Recently, our program has been converted for use in modeling a magnetic storm and one run has been made through the first few hours of the magnetic storm of 29 July 1977. A realistic model ring current was injected in the first few hours after the sudden commencement.

Subject Categories:

  • Atmospheric Physics
  • Geomagnetism

Distribution Statement: