The Solar Wind.pdf

• The solar wind speed and density have large variations ontime scales of days. Of special interest are high speedstreams.– The flow speed varies from pre-stream levels (400 km/s) reaching amaximum value (600 km/s – 700 km/s) in about one day.– The density rises to high values (>50 cm -3 ) near the leading edgesof the streams and these high densities generally persist for about aday. The peaks are followed by low densities lasting several days.– The proton temperature varies like the flow speed.– The high speed streams tend to have a dominant magnetic polarity.– The dominant source of high speed streams is thought to be fieldlines that are open to interplanetary space. These regions areknown as coronal holes.