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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, A07S14, doi:10.1029/2005JA011394, 2006

The 17–22 October (1999) solar-interplanetary-geomagnetic event: Very intense geomagnetic storm associated with a pressure balance between interplanetary coronal mass ejection and a high-speed stream

Alisson Dal Lago

Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


Walter D. Gonzalez

Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


Laura A. Balmaceda

Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany


Luis E. A. Vieira

Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


Ezequiel Echer

Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


Fernando L. Guarnieri

Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


Jean Santos

Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany


Marlos R. da Silva

Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


Aline de Lucas

Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


Alicia L. Clua de Gonzalez

Instituto Nacional de Pesquisas Espaciais, São José dos Campos, São Paulo, Brazil


Ranier Schwenn

Max-Planck-Institut für Sonnensystemforschung, Katlenburg-Lindau, Germany


Nelson J. Schuch

Centro Regional Sul de Pesquisas Espaciais, Santa Maria, Rio Grande do Sol, Brazil


Abstract

Using observations from the Advanced Composition Explorer (ACE) magnetic field and plasma experiments, we investigate the magnetic, thermal, and dynamic pressure balance in the border of a high-speed stream (HSS) and an average-speed interplanetary coronal mass ejection (ICME) observed on 21–22 October (1999). We believe that the HSS compressed the ICME and intensified its internal southward magnetic field, resulting in a very intense geomagnetic storm, with peak Dst of −237 nT. In solar cycle 23 this was the only event, out of 18 very intense geomagnetic storms, i.e., peak Dst < −200 nT, which was caused by such a mechanism. We also address the solar origin of this very intense geomagnetic storm, using combined solar data from three different sources: a ground-based source, coronal hole maps from the National Solar Observatory (NSO) at Kitt Peak, and two satellite-based sources, eruption activity from the Extreme Ultraviolet Imaging Telescope (EIT) and coronal mass ejection observations from the Large Angle and Spectrometric Coronagraph (LASCO), both aboard the Solar and Heliospheric Observatory (SOHO). A coronal hole is evident just beside (to the east of) the active region from which an average-speed coronal mass ejection lifted off on 17–18 October (1999). This was the only possible solar origin of the 21–22 October interplanetary geomagnetic event.

Received 31 August 2005; accepted 28 March 2006; published 22 June 2006.

Keywords: coronal mass ejections; geomagnetic storms; speed streams.

Index Terms: 2788 Magnetospheric Physics: Magnetic storms and substorms (7954); 7513 Solar Physics, Astrophysics, and Astronomy: Coronal mass ejections (2101); 7511 Solar Physics, Astrophysics, and Astronomy: Coronal holes; 2111 Interplanetary Physics: Ejecta, driver gases, and magnetic clouds; 2102 Interplanetary Physics: Corotating streams.


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Citation: Dal Lago, A., et al. (2006), The 17–22 October (1999) solar-interplanetary-geomagnetic event: Very intense geomagnetic storm associated with a pressure balance between interplanetary coronal mass ejection and a high-speed stream, J. Geophys. Res., 111, A07S14, doi:10.1029/2005JA011394.