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Detailed Reference Information |
Vaisberg, O.L., Smirnov, V.N., Avanov, L.A., Waite, J.H., Burch, J.L., Gallagher, D.L. and Borodkova, N.L. (2001). Different types of low-latitude boundary layer as observed by Interball Tail probe. Journal of Geophysical Research 106: doi: 10.1029/2000JA000154. issn: 0148-0227. |
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Interball Tail probe crossed dayside magnetopause during late winter to middle autumn months. The high-latitude magnetopause was crossed outbound orbit, while the low-latitude magnetopause was crossed inbound. We analyze 31 low-latitude magnetopause/low-latitude boundary layer (LLBL) crossings recorded in 1996 in the fast mode of SCA-1 ion spectrometer. Data from the MIF/FM-3 magnetometers and ELECTRON spectrometer are also used. The majority of magnetopause/LLBL crossings fall into two categories: (1) highly structured LLBL (14 cases) and (2) weakly structured LLBL (9 cases). The highly structured LLBL usually consists of short-time (0.5--5 min) transients including fast-moving (of an order of magnetosheath velocity) plasma as well as density transients that are nearly stationary relative to the magnetospheric plasma. The observed ensemble of transients shows evolution of plasma parameters from magnetosheath-like to magnetosphere-like. Fast-moving transients frequently have flux transfer event (FTE) magnetic signatures. This type of LLBL is usually accompanied by various reconnection signatures and is more frequently observed when the interplanetary magnetic field (IMF) and/or magnetosheath magnetic field has a negative Bz component. The weakly structured LLBL shows a significantly smaller variation of number density and hotter plasma temperature. Strong velocity shear is frequently observed at the magnetopause in the weakly structured case. Dispersed ion signatures are often seen within this type of LLBL. The ion and electron temperatures within the weakly structured LLBL are more elevated in respect to the magnetosheath values compared to the highly structured LLBL. The weakly structured LLBL has a tendency to occur at positive IMF and/or magnetosheath magnetic field Bz. The cause of significant differences between the two kinds of LLBL lies, apparently, in the significantly larger distance of the plasma entry site from the observation point, for weakly structured LLBL, as opposed to highly structured LLBL. While the highly structured LLBL originates at low latitudes, the weakly structured LLBL is most probably formed at high latitudes. ¿ 2001 American Geophysical Union |
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Abstract |
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Keywords
Magnetospheric Physics, Magnetopause, cusp, and boundary layers, Magnetospheric Physics, Solar wind/magnetosphere 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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