Tracking intense geomagnetic storms to the interplanetary medium and solar sources

SCHMIEDER, B.; DASSO, S.; MANDRINI, C.H.; DÉMOULIN, P.; ZHUKOV, A.; ARAN, A.; CERRATO, Y.; CID, C.; CREMADES, H.; MENVIELLE, M.; POEDTS, S.; RODRIGUEZ, L.; SAIZ, E.

Berlín

Simposio; SCOSTEP Symposium 2010 - STP12; 2010

Scientific Committee on Solar-Terrestrial Physics

On May 15, 2005, at 02:38 UT an interplanetary shock was recorded by ACE. The following interplanetary structure produced an important geomagnetic storm (minimal value of the Dst index -263 nT). Analysis of interplanetary (plasma and magnetic) observations has shown that these disturbances could correspond to the arrival of magnetic clouds. The main trigger of the geomagnetic storm is definitively the fast halo CME of May 13 (LASCO) observed consequently to the flare occurring at 17:22 UT in the active region 10759. However, the analysis of the complexity of the magnetic cloud parameters (ACE) leads us to different possible scenarios for the interpretation. The existence of two clouds produced by two different solar events on May 13 (two different filament eruptions) is the more probable scenario. The agreement between the magnetic helicity sign in the source region and the magnetic clouds, together with the agreement between the MC axis orientations and the polarity inversion line directions, support this view.