Low-frequency (1.7–6.7 mHz) geomagnetic-field fluctuations at high southern latitudes
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The low-frequency (1.7–6.7 mHz) powers of the horizontal componentsH andD recorded at the Antarctic Italian geomagnetic observatory at Terra Nova Bay (geomagnetic coordinates 77.3S, 279.4 E) during the austral summers 1987/1988 and 1989/1990 have been analysed. The activity level is higher during 1989/1990, corresponding to solar maximum, and theD power is always higher than theH one. The daily power distribution shows, for both components, a significative activity enhancement around the magnetic local noon, which more clearly emerges during quiet magnetospheric conditions. Good correlations have been obtained between the low-frequency power and the solar-wind velocity, the IMF standard deviation and theK p index, suggesting that the low-frequency power is linked both to theK-H instability and to the penetration into the magnetosphere of interplanetary turbulence. Correlation coefficients attain minimum values around the magnetic local noon, when the power level is higher.
PACS 94.30Physics of the magnetosphere
PACS 94.30.MsMagnetic pulsations
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- Lanzerotti L. J., inUpper Atmosphere Research in Antarctica, Antarct. Res. Ser., edited byL. J. Lanzerotti andC. G. Park, Vol.29 (AGU, Washington, D.C.), 1978, pp. 130–156.Google Scholar
- Rodger A. S.,Proceedings of the Workshop on CLUSTER dayside polar cusp (Svalbard, Norway, 16–19 Sept. 1991), edited byC. I. Barron, Vol. SP-330 (ESA Publications Division) 1991, pp. 35–41.Google Scholar
- Meloni A., De Santis A., Morelli A., Palangio P., Romeo G., Bozzo E. andCaneva G., inRecent Progress in Antarctic Earth Science, edited byY. Yoshida et al. (TERRAPUB, Tokyo) 1992, pp. 585–588.Google Scholar
- Ballatore P., Cafarella L., Candidi M. andMeloni A., Internal Report CNR (1994) IFSI-94-20.Google Scholar
- Lepidi S., Villante U., Vellante M., Palangio P. andMeloni A.,Ann. Geofis.,34 (1996) 519.Google Scholar
- Azzara R., Bozzo E., Caneva G., Meloni A., Palangio P. andRomeo G.,Mem. Soc. Geol. It.,46 (1991) 585.Google Scholar
- Chapman S. andBartels J.,Geomagnetism,1, (1951) 338.Google Scholar
- Anderson B. J., inSolar Wind Sources of Magnetospheric Ultra-Low-Frequency Waves, Geophys. Monogr. Ser., edited byM. J. Engebretson, K. Takahashi andM. Scholer, Vol.81 (AGU, Washington D.C.) 1994, pp. 25–43.Google Scholar