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Detailed Reference Information |
Gjerloev, J.W. and Hoffman, R.A. (2000). Height-integrated conductivity in auroral substorms: 2. Modeling. Journal of Geophysical Research 105: doi: 10.1029/1999JA900353. issn: 0148-0227. |
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Calculations of height-integrated conductivity from 31 individual Dynamics Explorer (DE 2) substorm crossing presented by Gjerloev and Hoffman [this issue> are used to compile empirical models of the height-integrated Pedersen and Hall conductivities (conductances) in a bulge-type auroral substorm. Global auroral images obtained by Dynamics Explorer 1 (DE 1) were used to select substorms displaying a typical bulge-type emission pattern and each individual DE 2 pass was positioned with respect to key features in the observed emission pattern. The conductances were calculated for each DE 2 pass using electron precipitation data and a monoenergetic conductance model. All passes were divided into six different sectors, and average conductance profiles were carefully deduced for each of these sectors. Using a simple boxcar filter, smoothed average sector passes were calculated and from linear interpolation between these, two-dimensional conductance models were compiled. The characteristics of our models are (1) the Hall conductance maximizes in the high-latitude part of the surge at 48 mho with a Hall to Pedersen ratio of 2.4; (2) two channels of enhanced conductance are overlapping in local time near midnight and are fairly separated in latitude; (3) the conductance has a sharp gradient at the high-latitude boundary in the premidnight sector while in the postmidnight sector a broad region of low conductance stretches up to 10¿ invariant latitude poleward of the local peak; and finally, (4) the enhanced conductance region displays a characteristic broadening toward dawn primarily owing to a poleward shift of the high-latitude boundary. ¿ 2000 American Geophysical Union |
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Abstract |
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Keywords
Ionosphere, Auroral ionosphere, Ionosphere, Modeling and forecasting, Magnetospheric Physics, Auroral phenomena, Magnetospheric Physics, Storms and substorms |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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