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Session 1 - Chromosphere, Corona, Flares.
Display session, Friday, June 27
Ballroom B, Chair: Charles Kankelborg

[1.29] The Origin and Acceleration of the Solar Wind

G. E. Brueckner (NRL)

The two distinctly different types of solar wind, the slow, low latitude and the fast polar wind have been identified in LASCO movies:

The slow, low latitude solar winds originates in the equatorial current sheet of the Sun. Mass and energy are supplied by expanding loops in the lower corona. Emerging magnetic flux must be the driver of the loop expansion. The expanding loops are confined inside the current sheet, which is formed by equatorially bend magnetic field of opposite polarity from the edges of the north and south polar coronal holes.

The current sheet serves as a mass and energy reservoir. Plasmoids are ejected after the current sheet cannot anymore reconnect newly injected magnetic field from the ascending loops. These plasmoids are accelerated from the lower corona to the edge of the field of view at 32 solar radii. They form the irregular structure of the slow solar wind, as it is observed at the Earth and beyond.

Faster outflow can be observed in the straight structures of the polar plumes. Flows are steady because of the open magnetic fields over the solar poles. A reservoir effect does not exist there. The acceleration takes place closer to the surface of the Sun, than at the equator. Gusts exists, but they are much less pronounced, compared with the equatorial wind. They can be used to measure the wind speed.


Program listing for Friday