Recurrent Activity caused by the Solar Wind

Above we have talked about coronal mass ejections travelling thoguh the interplanetary medium to cause space weather effects at the Earth. These are transient disturbances and take place at random intervals. These disturbances are superimposed over a background solar wind. This is a persistent flow of ionised solar plasma and a remnant of the solar magnetic field which spreads out in a spiral pattern, sometimes compared to a twirling ballerina's skirt. Although it is always present, the solar wind does not always flow at the same speed. Different parts travel faster than others. As a result the faster parts catch up with the preceeding slower parts and alternating regions of dense particles and fields and less dense regions are formed. The passage of these regions called co-rotating interaction regions as they sweep by the Earth's magnetosphere induces geomagnetic activity through variations of the solar wind pressure and magnetic field orientation at the Earth's magnetopause.

SOHO Solar Wind Data The latest 48 hours of solar wind data from the Proton Monitor on the SOHO spacecraft provided by the University of Maryland, USA.  

Future missions such as the proposed ESA Solar Orbiter mission together with the Solar Dynamics Observatory, part of NASA's Living with a Star programme, the NASA STEREO mission and the ISAS/NASA Solar-B mission will all help to further our understanding of solar activity.

Coronal Mass Ejections