ocr: Not all solar flares result in mag- netic storms, and, even nore sig- nificantly, not all geomagnenc storms can be associated with so- lar flares. Some of the most dra- matic space weather # eftects oC cur in association with eruptions ofmaterial from the solar otmos- phere into interplanetary space. These eruptions are known 05 coronal mass ejections, or CMES. Such eruptions are sometimes associated with flares, and they now appear to be a primary cause of geomagnetic activity.
