The sun flings out solar wind particles in much the same manner as a garden sprinkler throws out water droplets.
The artist's drawing of the solar wind flow was provided courtesy of NASA.
The Spiral of the IMF
The solar wind is formed as the Sun's top layer blows off into space. It carries magnetic fields still attached to the Sun.
Streams appear to flow into space as if they are spiraling out from the Sun, as shown in this figure. This is called the "spiral angle" of the IMF (interplanetary magnetic field).
Planets have to be in a stream's path to be affected.
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