HR: 0830h
AN: SM51C-0554    [PDF]
TI: The SSC event of April 17 2002:a preliminary analysis from SEGMA array.
AU: Villante, U
EM: umberto.villante@aquila.infn.it
AF: Universit… degli studi de l'Aquila, via Vetoio, Coppito, AQ 67010 Italy
AU: * Piersanti, M
EM: mirko.piersanti@aquila.infn.it
AF: Universit… degli studi de l'Aquila, via Vetoio, Coppito, AQ 67010 Italy
AU: Di Giuseppe, P
EM: paolo.digiuseppe@aquila.infn.it
AF: Universit… degli studi de l'Aquila, via Vetoio, Coppito, AQ 67010 Italy
AU: Vellante, M
EM: massimo.vellante@aquila.infn.it
AF: Universit… degli studi de l'Aquila, via Vetoio, Coppito, AQ 67010 Italy
AU: Magnes, W
EM: werner.magnes@oeaw.ac.at
AF: Institut fuer Weltraumforschung, Schmiedlstraáe 6, Graz, 8042 Austria
AU: Zang, T
EM: tielong.zhang@oeaw.ac.at
AF: Institut fuer Weltraumforschung, Schmiedlstraáe 6, Graz, 8042 Austria
AB: \textbf{Abstract}. We conducted a multi-station analysis of the April 17, 2002 SSC by means of high resolution measurements (1 second) conducted at three stations of SEGMA, the new South European Geomagnetic Array (Nagycenk, NCK, Mlat. 42.68$^{\circ}$, Ranchio, RNC, Mlat. 38.19$^{\circ}$, L'Aquila, AQU, Mlat. 36.22$^{\circ}$, along the same geomagnetic meridian $\sim$90$^{\circ}$). The characteristics of both the main impulse (MI) and the preliminary impulse (PI) are analyzed as a function of magnetic latitude. The PI is characterized by a positive variation along H and a negative variation along D. It is accompanied by a clear Pc3 wave activity at discrete frequencies ($^{\sim}$40 mHz and $^{\sim}$60 mHz). We adopted also a different approach in which the geomagnetic signal is decomposed along axes associated with maximum ($V_{max}$) and minimum variance ($V_{min}$) orientation. The MI field, along $V_{max}$, is oriented at ~ 45$^{\circ}$ from the H component; conversely, the PI field has a dominant component along $V_{min}$.
DE: 2788 Storms and substorms
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting