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Solar Wind Speeds

Date: 12 June 2008
Depicts: Solar wind speeds at solar minimum and maximum
Copyright: ESA

Before Ulysses, it was known that two types of solar wind existed: a fast wind which was considered to be unusual, and a slow wind which was considered more typical.  It was not known how the solar wind varied with solar latitude.

Ulysses discovered that the fast wind is basically present throughout the whole 11-year solar cycle and disappears only at solar maximum. At solar minimum (left panel) the fast wind fans out from the poles to fill two thirds of the heliosphere, blowing at an average uniform speed of 750 kms-1 (see arrows), much faster than the wind (with typical speeds of 350 kms-1) that emerges from the Sun's equatorial zone. At solar maximum (right panel) the solar wind is more turbulent and irregular.

Last Update: 13 June 2008

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