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It is generally accepted that extreme space weather events tend to be related to strong flares and fast halo coronal mass ejections CMEs. In the present paper, we carefully identify the chain of events from the Sun to the Earth induced by all 12 X-class flares that occurred in 2002. In this small sample, we find an unusual high rate (58\%) of solar sources with a longitude larger than 74 degrees. Yet, all 12 X-class flares are associated with at least one CME. The fast halo CMEs (50\% ) are related to interplanetary CMEs (ICMEs) at L1 and weak Dst minimum values ($> -51\;$nT); while 5 (41\%) of the 12 X-class flares are related to solar proton events (SPE). We conclude that: (i) All twelve analyzed solar events, even those associated with fast halo CMEs originating from the central disk region, and those ICMEs and SPEs were not very geo-effective. This unexpected result demonstrates that the suggested events in the chain (fast halo CME, X-class flares, central disk region, ICME, SPE) are not infallible proxies for geo-effectiveness. (ii) The low value of integrated and normalized southward component of the IMF ($B^*_z$) may explain the low geo-effectiveness for this small sample. In fact, $B^*_z$ is well correlated to the weak Dst and low auroral electrojet (AE) activity. Hence, the only space weather impact at Earth in 2002 we can explain is based on $B^*_z$ at L1., Comment: 33 pages, 12 figures

We investigate the solar phenomena associated with the origin of the solar energetic particle (SEP) event observed on 2013 April 11 by a number of spacecraft distributed in the inner heliosphere over a broad range of heliolongitudes. We use Extreme UltraViolet (EUV) and white-light coronagraph observations from the Solar Dynamics Observatory (SDO), the SOlar and Heliospheric Observatory (SOHO) and the twin Solar TErrestrial RElations Observatory spacecraft (STEREO-A and STEREO-B) to determine the angular extent of the EUV wave and coronal mass ejection (CME) associated with the origin of the SEP event. We compare the estimated release time of SEPs observed at each spacecraft with the arrival time of the structures associated with the CME at the footpoints of the field lines connecting each spacecraft with the Sun. Whereas the arrival of the EUV wave and CME-driven shock at the footpoint of STEREO-B is consistent, within uncertainties, with the release time of the particles observed by this spacecraft, the EUV wave never reached the footpoint of the field lines connecting near-Earth observers with the Sun, even though an intense SEP event was observed there. We show that the west flank of the CME-driven shock propagating at high altitudes above the solar surface was most likely the source of the particles observed near Earth, but it did not leave any EUV trace on the solar disk. We conclude that the angular extent of the EUV wave on the solar surface did not agree with the longitudinal extent of the SEP event in the heliosphere. Hence EUV waves cannot be used reliably as a proxy for the solar phenomena that accelerates and injects energetic particles over broad ranges of longitudes.