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Article Images
Cluster monitors convection cells over the polar caps
 
22 October 2007

Artist's impression of Cluster
Flying in formation around the Earth, they relay detailed information about how solar wind affects our planet in 3D. The satellites are called Rumba, Salsa, Samba and Tango.

Credits: ESA
 
 
The Sun-Earth connection
Download:
 HI-RES JPEG (Size: 450 kb)
Although Earth is vastly protected from the hazards of interplanetary space by the magnetosphere and atmosphere, they do not form an isolated bubble.

The solar wind, a stream of particles continuously blowing from the Sun, compresses Earth’s magnetosphere on the dayside and stretches it into a long tail on the nightside. Most solar wind is deflected by the magnetosphere but some material manages to enter. Understanding how this works is of crucial importance to space-borne infrastructure (GPS, telecommunication satellites) and for the safety of astronauts.

One way to monitor this interaction is to study the convection cells.

For the first time, statistical maps of the convection cells under various solar conditions were derived `with six years of data from ESA's Cluster mission.

Credits: NASA

 
 
Download:
 HI-RES JPEG (Size: 2800 kb)
This video shows the pattern of convection cells above the polar caps for different orientations of the Interplanetary Magnetic Field.

Although Earth is vastly protected from the hazards of interplanetary space by the magnetosphere and atmosphere, they do not form an isolated bubble. Most incoming solar wind is deflected by the magnetosphere but some material manages to enter. Understanding the mechanism is of crucial importance to space-borne infrastructure (GPS, telecommunication satellites) and for the safety of astronauts.

One way to do this is to study the convection cells.

For the first time, statistical maps of the convection cells under various solar conditions were derived `with six years of data from ESA's Cluster mission. Results show that the behaviour of the cells is linked heavily to solar activity.

It can be clearly seen that the number of cells varies depending on the orientation of the IMF.

Credits: Max-Planck-Institut für extraterrestrische Physik (S. Haaland)

 
 
Differing patterns in the convection cells
Download:
 HI-RES JPEG (Size: 870 kb)
This picture shows the pattern of convection cells above the polar caps for different orientations of the Interplanetary Magnetic Field.

Although Earth is vastly protected from the hazards of interplanetary space by the magnetosphere and atmosphere, they do not form an isolated bubble. Most incoming solar wind is deflected by the magnetosphere but some material manages to enter. Understanding the mechanism is of crucial importance to space-borne infrastructure (GPS, telecommunication satellites) and for the safety of astronauts.

One way to do this is to study the convection cells.

For the first time, statistical maps of the convection cells under various solar conditions were derived `with six years of data from ESA's Cluster mission. Results show that the behaviour of the cells is linked heavily to solar activity.

The left panel shows the convection pattern in the cells for the IMF directed southward directed as per Cluster EDI measurements

The right panel shows the convection cell pattern for the IMF directed northward as per Cluster EDI measurements

It can be clearly seen that the number of cells varies depending on the orientation of the IMF.

Credits: Max-Planck-Institut für extraterrestrische Physik (S. Haaland)

 
 
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Cluster overviewDouble Star overviewSOHO overviewSolar OrbiterSpace weather
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Related links
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