Extreme geoeffective events

SCHMIEDER, B.; CID, C.; CREMADES, H.; MANDRINI, C.H.

Nagoya

Conferencia; International Climate and Weather of the Sun-Earth System II Conference; 2013

SCOSTEP

Intense flares are responsible of  geoeffective events with two different time scales. Some minutes after the flare high-energy particles following the Parker spiral may hit the  Earth atmosphere. In general, their flux is not high enough to produce a catastrophe; only one to ten events per year are dangerous. One day to five days after the flare,  coronal mass ejections (CME) facing the Earth are the potential cause of the major geomagnetic storms.  There are in average two CMEs per day, so the risk is high.  To prevent major storms, it is important to understand which and where is the solar source,  the transport of the coronal mass ejection through the interplanetary medium and its impact on the magnetosphere.  The  link   between CMEs and geomagnetic events is understood using in situ measurements (from e.g. ACE, Wind).  The link between CMEs and their solar sources using imagers and coronographs (SOHO, STEREO, SDO).  We will present some extreme events and discuss all the problems we face to understand the phenomena from one to the other end.