The solar source of extreme space weather events

L. BALMACEDA; A. DAL LAGO; H. CREMADES; E. ECHER; R. RAWAT; L. E. A. VIEIRA

La Roche-en-Ardenne

Workshop; Solar Information Processing Workshop; 2014

Extreme space weather events, i.e. that cause very intense geomagnetic storms with Dst < -400nT, such as the Carrington event in 1859 or the 1989 storm seldom occur during a solar cycle. On 23 July 2012, STEREO-A spacecraft observed an extremely fast coronal mass ejection (CME) that traveled a distance of about 1 AU in approximately 18 h. The event called the attention of the scientific community and became the target of several modeling studies which analyze the hypothetical response of the magnetosphere if this CME would have been directed to the Earth. The estimated Dst index for such a storm was less than -1000 nT. Here we investigate the morphological characteristics of the source on the solar surface and study the initial conditions that trigger the eruption. We use EUV images from STEREO and SDO in order to reconstruct the 3D structure of the CME in the lower corona and infere the true direction of propagation. We further examine the in-situ data in order to study its counterpart in the interplanetary medium. Finally, we compare the overall characteristics of this event with the November 2003 extreme event from previous solar cycle.