How does the solar wind work?
The surface of the Sun is an environment filled with ionized gas and magnetic fields. The magnetic fields are not randomly oriented in space but come in more or less two distinct types. Closed field lines emerge from the surface, loop up into space into the chromosphere or corona, and then connect back on the surface. These are the ones that account for the beautiful patterns of heated gases you see in the YOHKOH X-ray image in Plate 1. Open field lines, however, stretch out into interplanetary space. Satellite observations directly show that the open field lines act like magnetic pipes down which the heated plasma from the solar corona and inner corona can escape if heated enough, usually by solar flares. These are seen as coronal holes in X- ray photographs of the sun, and they come and go depending on the activity level of the sun. The dark patch at the top of the YOHKOH image of the Sun (Plate 1) shows what such a hole looks like. There is also a constant wind emitted by the Sun du
