TY  - JOUR
AU  - Yagova, N. V.
AU  - Pilipenko, V. A.
AU  - Lanzerotti, L. J.
AU  - Engebretson, M. J.
AU  - Rodger, A. S.
AU  - Lepidi, S.
AU  - Papitashvili, V. O.
PY  - 2004//
TI  - Two-dimensional structure of long-period pulsations at polar latitudes in Antarctica
T2  - J. Geophys. Res.
JO  - Journal of geophysical research-atmospheres
VL  - 109
PB  - American Geophysical Union
KW  - 2776 Magnetospheric Physics: Polar cap phenomena
KW  - 2752 Magnetospheric Physics: MHD waves and instabilities
KW  - 2744 Magnetospheric Physics: Magnetotail
KW  - 2724 Magnetospheric Physics: Magnetopause
KW  - cusp
KW  - and boundary layers
N2  - Two-dimensional (2-D) statistical distributions of spectral power and coherence of polar geomagnetic variations with quasi-periods about 10 min are analyzed using data from magnetometer arrays in Antarctica. Examination of the 2-D patterns of spectral power and coherence shows the occurrence of significant variations in geomagnetic power levels but with low spatial coherence near the cusp projection and in the auroral region. At the same time, low-amplitude pulsations, which we coin Pi cap3 pulsations, are very coherent throughout the polar cap. The region occupied by coherent Pi cap3 pulsations is shifted toward local MLT night from the geomagnetic pole and is decoupled from the regions of auroral and cusp ULF activity. The spectral power varies with time at polar latitudes in a manner different from that at auroral latitudes. Diurnal variations of power at different stations at the same geomagnetic latitude exhibit different behavior depending on the station's position relative to geomagnetic and geographic poles. This asymmetry is shown to be partly attributed to the variations of the ionospheric conductance. The primary source of polar pulsations is probably related to intermittent magnetosheath turbulence and tail lobe oscillations, though a particular propagation mechanism has not as yet been identified.
SN  - 0148-0227
UR  - http://dx.doi.org/10.1029/2003JA010166
N1  - exported from refbase (http://publi.ipev.fr/polar_references/show.php?record=5539), last updated on Mon, 20 Apr 2009 14:00:27 +0200
ID  - Yagova_etal2004
ER  -