Pc3 pulsations during variable IMF conditions

Pc3 geomagnetic field fluctuations detected at low latitude (L'Aquila, Italy) during the passage of a high velocity solar wind stream, characterized by variable interplanetary magnetic field conditions, are analyzed. Higher frequency resonant fluctuations and lower frequency phenomena are simultaneously observed; the intermittent appearance and the variable frequency of the longer period modes can be well interpreted in terms of the variable IMF elements; moreover their polarization characteristics are consistent with an origin related to external waves propagating in antisunward direction. A comparison with simultaneous observations performed at Terra Nova Bay (Antarctica) provides additional evidence for a clear relationship between the IMF and Pc3 pulsations also at very high latitudes.

Ansari, I. A., and B. J. Fraser, A multistation study of low
latitude Pc3 geomagnetic pulsations, Planet. Space Sci., 34,
519, 1986.
Baransky, L. N., S. P. Belokris, U. E. Borovkov, and C. A. Green,
Two simple methods for the determination of the resonance
frequencies of magnetic ®eld lines, Planet. Space Sci., 38, 1573,
1990.
Chen, L., and A. Hasegawa, A theory of long-period magnetic
pulsations, 1, steady state excitation of ®eld line resonances, J.
Geophys. Res., 79, 1024, 1974.
Chi, P. J., C. T. Russell, and G. Le, Pc3 and Pc4 activity during a
long period of low interplanetary magnetic ®eld cone angle as
detected across the Institute of Geological Sciences array, J.
Geophys. Res., 99, 11127, 1994.
Engebretson M. J., C.-I. Meng, R. L. Arnoldy, and L. J. Cahill, Jr.,
Pc3 pulsations observed near the south polar cusp, J. Geophys.
Res., 91, 8909, 1986.
Engebretson M. J., B. J. Anderson, L. J. Cahill, Jr., R. L. Arnoldy,
P. T. Newell, C.-I. Meng, L. J. Zanetti, and T. A. Potemra, A
multipoint case study of high latitude daytime ULF pulsations,
J. Geophys. Res., 94, 17 143, 1989.
Engebretson M. J., L. J. Cahill, Jr., R. L. Arnoldy, B. J. Anderson,
T. J. Rosenberg, D. L. Carpenter, U. S. Inan, and R. H. Eather,
The role of the ionosphere in coupling upstream ULF wave
power into the dayside magnetosphere, J. Geophys. Res., 96,
1527, 1991.
Farrugia, C. J., M. P. Freeman, S. W. H. Cowley, D. J. Southwood,
M. Lockwood, and A. Etemadi, Pressure driven magnetopause
motions and attendant response on the ground, Planet. Space
Sci., 37, 589, 1989.
Green, A. W., E. W. Worthington, L. N. Baransky, E. N. Fedorov,
N. A. Kurneva, V. A. Pilipenko, D. N. Shvetzov, A. A.
Bektemirov, and G. V. Philipov, Alfve n ®eld line resonances at
low-latitudes (L = 1.5), J. Geophys. Res., 98, 15 693, 1993.
Greenstadt, E. W., and J. V. Olson, Pc3,4 activity and interplan-
etary ®eld orientation, J. Geophys. Res., 81, 5911, 1976.
Greenstadt, E. W., R. L. McPherron, and K. Takahashi, Solar wind
control of daytime, midperiod geomagnetic pulsations, J.
Geomagn Geoelectr., 32 (11), 89, 1980.
Lanzerotti, L. J., L. V. Medford, C. G. Maclennan, T. Hasegawa,
M. H. Acuna, and S. R. Dolce, Polarization characteristics of
hydromagnetic waves at low geomagnetic latitudes, J. Geophys.
Res., 86, 5500, 1981.
Le, G., and C. T. Russell, Solar wind control of upstream wave
frequency, J. Geophys. Res., 101, 2571, 1996.
Lepidi, S., U. Villante, M. Vellante, P. Palangio, and A. Meloni,
High resolution geomagnetic ®eld observations at Terra Nova
Bay, Antarctica, Ann. Geo®s., 34, 519, 1996.
Odera, T. J., Solar wind controlled pulsations: a review, Rev.
Geophys., 24, 55, 1986.
Russell, C. T., J. G. Luhmann, T. J. Odera, and W. F. Stuart, The
rate of occurrence of dayside Pc3,4 pulsations: the L-value
dependence of the IMF cone angle e ect, J. Geophys. Res., 10,
663, 1983.
Southwood, D. J., Some features of ®eld-line resonances in the
magnetosphere, Planet. Space Sci., 22, 483, 1974.
Troitskaya, V. A., and O. V. Bolshakova, Diagnostics of the
magnetosphere using multipoint measurements of ULF-waves,
Adv. Space Res., 8, 413, 1988.
Vellante, M., U. Villante, M. De Lauretis, and P. Cerulli-Irelli, An
analysis of micropulsation events at a low-latitude station
during 1985, Planet. Space Sci., 37, 767, 1989.
Vellante, M., U. Villante, R. Core, A. Best, D. Lenners, and V. A.
Pilipenko, Simultaneous geomagnetic pulsation observations at
two latitudes: resonant mode characteristics, Ann. Geophysicae,
11, 734, 1993.
Vellante, M., U. Villante, M. De Lauretis, G. Barchi, Solar cycle
variation of the dominant frequencies of Pc3 geomagnetic
pulsations at L = 1.6, Geophys. Res. Lett., 23, 1505, 1996.
Villante, U., S. Lepidi, M. Vellante, A. J. Lazarus, and R. P. Lepping,
Pc3 activity at low geomagnetic latitudes: a comparison with solar
wind observations, Planet. Space Sci., 40, 1399, 1992.
Villante, U., M. De Lauretis, P. Francia, S. Lepidi, L. Cafarella, A.
Meloni, A. J. Lazarus, R. P. Lepping, and F. Mariani, Low
frequency geomagnetic ®eld variations at low and high latitude
during the January 10±11, 1997 magnetic cloud, Geophys. Res.
Lett., 25, 2593, 1998.
Waters, C. L., F. W. Menk, and B. J. Fraser, Low latitude
geomagnetic ®eld line resonance: experiment and modeling, J.
Geophys. Res., 99, 17 547, 1994.
Webb, D., and D. Orr, Geomagnetic pulsations (5±50 mHz) and
the interplanetary magnetic ®eld, J. Geophys. Res., 81, 5941,
1976.
Yumoto, K., Generation and propagation mechanisms of low-
latitude magnetic pulsations ± a review, J. Geophys., 60, 79,
1986.
Yumoto, K., and T. Saito, Relation of compressional HM waves at
GOES 2 to low-latitude Pc3 magnetic pulsations, J. Geophys.
Res., 88, 10 041, 1983.
Yumoto, K., T. Saito, and Y. Tanaka, Low-latitude Pc3 magnetic
pulsations observed at conjugate stations (L 1.5), J. Geophys.
Res., 90, 12 201, 1985.
Yumoto, K., T. Saito, Y. Tanaka, K. J. W. Lynn, F. W. Menk, and
B. J. Fraser, Polarization and amplitude characteristics of Pc3
pulsations in conjugate area around L = 1.3±2.1, J. Geophys.
Res., 93, 7386, 1988.