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Detailed Reference Information |
Nosé, M., Iyemori, T., Sugiura, M., Slavin, J.A., Hoffman, R.A., Winningham, J.D. and Sato, N. (1998). Electron precipitation accompanying Pc 5 pulsations observed by the DE satellites and at a ground station. Journal of Geophysical Research 103: doi: 10.1029/98JA01187. issn: 0148-0227. |
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Using data from the polar orbiting Dynamic Explorer (DE) -1 and -2 satellites and a ground-based station, we investigated electron precipitation phenomena accompanying Pc 5 pulsations. DE-2 observed oscillatory disturbances in the magnetic and electric fields in the upper ionosphere at the geomagnetic footprint of the high altitude region in which transverse Pc 5 pulsations were detected by DE-1. DE-2 observed electrons precipitating into the ionosphere with energies of several keV to several tens of keV. These electrons were accelerated in the direction of the ambient magnetic field. When Pc 5 pulsations in the H-component and periodic variations of cosmic radio noise absorption (CNA pulsations) were observed at Syowa Station, DE-2 which was in geomagnetic conjunction with Syowa Station also observed oscillatory disturbances in the magnetic and electric fields. These oscillatory disturbances are caused by small-scale field-aligned currents each with width of 0.5¿--1.4¿ invariant latitude. This suggests that Pc 5 pulsations have a small-scale resonance structure in the radial direction. The resonance structure has a small scale comparable to the ion acoustic gyroradius, then kinetic Alfv¿n waves having electric fields parallel to the ambient magnetic field can arise. The parallel electric field generates a field-aligned potential drop of about 3--5 kV. Electrons accelerated by these kinetic Alfv¿n waves would cause CNA pulsations, the phase of which leads that of the H-component of the Pc 5 pulsations by 90¿ in the southern hemisphere. This is consistent with the observations at Syowa Station. ¿ 1998 American Geophysical Union |
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Abstract |
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Keywords
Space Plasma Physics, Wave/particle interactions |
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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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