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Question:
Could someone please explain (in depth if possible) if a there is "solar wind" and how does it work in space. Please send the reply to punisher@m-net.arbornet.org ...please.


Replies:
From _Introductory Astronomy and Astrophysics_ by Smith and Jacobs: Interplanetary space beyond the solar corona is not empty. The high coronal temperatures imply a substantial pressure tending to blow the corona away from the Sun. The Sun's gravitational attraction on this gas is insufficient to retain it, so that there is a steadily flowing _solar wind_ leaving the Sun. This flowing gas, composed of approximately equal numbers of electrons and protons, is termed a plasma...; as it pervades the solar system it is called the _interplanetary medium_. The thermal conductivity of the plasma is very high, so that high temperatures prevail over great distances from the Sun. Hence, the wind accelerates as it expands (large-scale speeds near 300 km/sec at 30 R(sun), and 400 km/sec at 215 R(sun) = 1 AU), and the particle density decreases to an average of about 5 electrons and protons per cc at 1 AU. These "quiet Sun" characteristics of the solar wind have been measured by interplanetary space probes.

These comments also apply to stars in general, although the details of the "stellar wind" will, of course, vary from star to star.

Hawley



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