How is Solar Wind Caused? Venus Climate Orbiter "AKATSUKI" Elucidated Solar Wind Acceleration
Researchers at the Institute of Space and Astronautical Science (ISAS) and the University of Tokyo studied solar wind flowing a long distance from the Sun's vicinity, whose distance is about 20 times the radius of the Sun, and found that the wind drastically accelerated at around a location that is five times the radius away from the Sun. They also clarified that the acceleration of solar wind in such a faraway place was related to heating cause by an energy source of waves transmitting through solar wind.
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JAXA | How is Solar Wind Caused? Venus Climate Orbiter "AKATSUKI" Elucidated Solar Wind Acceleration