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Detailed Reference Information
Hughes et al. 1978
Hughes, W.J., McPherron, R.L. and Barfield, J.N. (1978). Geomagnetic pulsations observed simultaneously on three geostationary satellites. Journal of Geophysical Research 83: doi: 10.1029/JA083iA03p01109. issn: 0148-0227.

Simultaneous observations of magnetic pulsations have been made by three geostationary and so acting as an azimuthal array. Autospectral and cross-spectral analysis yields coherence and phase differences between the pulsations at the satellite positions. The majority of the data fit the Kelvin-Helmholtz generation mechanism. The azimuthal wave number changes sign near noon and corresponds to propagation away from noon. Usually, the wave number is >10¿ per degree of longitude. Later in the afternoon, however, strong pulsations are observed with low coherence, implying large wave numbers. This suggests an instability driven by a gradient in the intensity of energetic protons, which may be expected at this local time. The data also suggest that some of the observed phase difference between the azimuthal components is due to small separations in magnetic shell, whereas this is not the case for the radial components. This implies a localized field line resonance. We obtain estimates of 1/4 and 1/2 RE for the equatorial extent of the resonant region.

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Abstract

Journal
Journal of Geophysical Research
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American Geophysical Union
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