"The Day the Solar Wind Disappeared"
Many young stars, among them the sun, possess stellar winds. The solar wind produces the heliosphere, the region of the interplanetary medium within which the solar wind pressure exceeds that of the interstellar medium. The mass flux of the solar wind is insufficient to affect solar structure as a result of mass loss, but has a major effect on the magnetospheres of planets such as Jupiter and Earth. It confines the planetary magnetic field in the sunward direction and draws the field away from the sun to form the magnetotail.
This talk describes the properties of the solar wind,
and discusses recent observations when the wind exhibited an abnormally
low density (~0.05 cm-3) for about a day. The properties of the wind
and the character of Earth’s magnetosphere were greatly affected.
Although this event on 11 May 1999 was a very striking example, it was
not unique. Other similar events will be interpreted; the causes
of such occurrences are presently unknown.