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Detailed Reference Information |
Nilsson, H., Kirkwood, S. and Moretto, T. (1998). Incoherent scatter radar observations of the cusp acceleration region and cusp field-aligned currents. Journal of Geophysical Research 103. doi: 10.1029/98JA02269. issn: 0148-0227. |
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Incoherent scatter radar measurements are used to study the E region and lower F region in the cusp proper. At the equatorward edge of the cusp a region of enhanced ionization is found, indicating precipitation of either electrons of about 1 keV energy or protons of about 3 keV. The signature is found at the same altitude, around 150 km, as the maximum of the solar EUV produced ionization, but is clearly recognizable. The position and likely proton energies indicate that this is probably the ionospheric signature of the cusp acceleration region. Regions of low electron densities are also found in the same altitude region, which may be explained by downward field-aligned currents causing depletions in the E and lower F region. First-order estimates show that dense field-aligned currents are needed to cause the observed depletions, possibly as dense as 30 &mgr;A/m2. The ionization in the cusp acceleration region, and the depletion caused by downward field-aligned currents both influence the Pedersen conductivity of the ionosphere, and the resulting conductivity gradients strongly influence the small-scale field-aligned currents flowing in the cusp region. ¿ 1998 American Geophysical Union |
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BACKGROUND DATA FILES |
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Abstract |
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Keywords
Ionosphere, Electric fields, Ionosphere, Ionosphere/magnetosphere interactions, Ionosphere, Plasma temperature and density, Magnetospheric Physics, Magnetopause, cusp, and boundary layers |
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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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