Linking 12 X-class flares and CMEs to SEP events and geomagnetic disturbances in 2002

0521265 - ÚFA 2020 BE eng A - Abstract
Schmieder, B. - Kim, R. - Grison, Benjamin - Bocchialini, K. - Kwon, R.-Y.
Linking 12 X-class flares and CMEs to SEP events and geomagnetic disturbances in 2002.
16th European Space Weather Week. Brussels: Solar-Terrestrial Centre of Excellence (STCE), 2019.
[European Space Weather Week /16./. 18.11.2019-22.11.2019, Liège]
Institutional support: RVO:68378289
Keywords : geomagnetic storm * coronal mass ejections (CMEs) * solar energetic particles (SEPs)
OECD category: Fluids and plasma physics (including surface physics)
http://www.stce.be/esww2019/program/session_details.php?nr=5#

We analyse systematically the chain of events related to the 12 X-ray flares of X class occurring in 2002: source region, CME, ICME, magnetic field at L1, geomagnetic indices, and SEP. No high SEP, no intense geomagnetic storm are related to any of these flares. Only one of them is associated to medium SEPs and a moderate storm. Three others are associated with a weak storm (-50 nT < min(Dst) < -30 nT). 75 % of the flares are associated with a halo CME with a good correlation rate for the speed/flux of the flare. However the flare sources are mainly close to the limb (70%) which is not favour for geomagnetic disturbances. The most important parameter of the IMF is the Bz orientation. It seems that the CMEs launched with high speed (around 2000 km/s) avoid the Earth in our sample. The location of the solar source, the shape of the CME, and the shock front have a direct impact on the geo-effectiveness We conclude that the association of big flares and strong geomagnetic disturbances may be valid only for extreme or intense geomagnetic storms. Otherwise the magnetic energy of active regions is released in an unexpected way into thermal energy and kinetic energy or in ejections of energetic particles.
Permanent Link: http://hdl.handle.net/11104/0305898