Thursday 10 February 2011
to 16:00 at
Oskar Klein Auditorium
Eugene Parker (University of Chicago)
The development of the solar wind concept began long ago with the realization that the Sun lies at the “center” of a vast space. The Sun is a complex engine, convecting, rotating nonuniformly, and generating magnetic fields that create sunspots, flares, coronal mass ejections, and the million degree corona. The intermittent shaking of the magnetic field of Earth was the first evidence of solar corpuscular radiation. The anti-solar pointing of comet tails provided a map of that radiation. Recognizing the hydrodynamic character of solar corpuscular radiation uncovered the phenomenon of coronal expansion to supersonic velocities, and suggested the more appropriate term “solar wind”. It was evident, then, that the expanding corona pulled magnetic fields out from the Sun to form an Archimedean spiral out through the solar system. The supersonic wind and its spiral magnetic field sweep back the galactic cosmic rays while pushing away the interstellar wind and magnetic field to a distance of the order of 100 AU, forming the heliosphere.