The Physics
Factbook
An encyclopedia of scientific essays

Speed of the Solar Wind

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Bibliographic Entry Result
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Standardized
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Marion, B Jerry. Physics and the Physical Universe. John Wiley & Sons Inc, Canada, 1971, 333. "The magnetosphere is profoundly influenced by the so-called solar-wind, a continuous stream of protons and electrons that are ejected by the sun and, at the position of the earth, have velocities of about 400 km/s." 400 km/s
The New Encyclopedia Britannica. Volume 27, 15th edition, Macropaedia, 1768. "Traveling at a speed of 500 kilometers per second particles will reach the orbit of Saturn in one solar rotation-27 days but in that time period the source on the sun will have gone completely around." 500 km/s
Stix, Michael. The Sun. Springer Berlin Heidelberg, 1989. "As figure 9.11 illustrates, the solar wind velocity often remains high (700 km/s) during a few consecutive days." 700 km/s
Smith G, Alex. Radio Exploration of the Sun. D. Van Nostrand Company, Inc. 1967, 142. "On Quiet days … the solar wind streams past the Earth's orbit at speeds from 300 to 600 km/s!" 300-600 km/s
The Voyager Data page - MIT Space Plasma Group. 5/16/2004. "The outer atmosphere of the sun expands to form the Solar Wind, with average speeds of 400 km/s (roughly one million miles per hour)" 400 km/s

The Solar wind is basically wind coming out of the outer atmosphere of the sun beginning with about 4000 km above the Sun's visible surface and extending into space. This is called the corona. The Solar wind is composed of ions and electrons. The ion component consists mostly of protons (95%), with a small amount of doubly ionized helium and trace amounts of heavier ions. The solar wind blows off of the Sun in all directions at speeds of about 400m/s. The solar wind is not regular though. Even though it is always directed away from the Sun, it changes speed and carries with it magnetic clouds, interacting regions where high speed wind catches up with slow speed wind, and composition variations. Magnetic Clouds are produced in the solar wind when solar eruptions carry material off of the Sun along with implanted magnetic fields. Interactive regions are regions within the solar wind where streams of material moving at different speeds collide and interact with each other. The solar wind speed is at a high (800 km/s) over coronal holes and at a low (300 km/s) over streamers. Coronal holes are regions where the corona is dark and streamers are large cap-like coronal structures with long pointed peaks that usually cover sunspots and active regions. These high and low speed streams interact with each other and alternately pass by the Earth as the Sun rotates. These wind speed variations pound the Earth's magnetic field and can produce storms in the Earth's magnetosphere.

Roman Osatinski -- 2004