Solar Wind Formation
Source of the Solar Wind?
Plasma streams away from the solar surface at the edges of active regions and may contibrute a 1/4 of the solar wind's total material.
Sakao et al., Science, 318, 1585, 2007.. View full-size photo here.
Using EIS as a Speed Camera
Hinode's EIS instrument reveals that the outflowing streams of plasma from the edges of active regions can reach speeds of over 100 km/s.
Harra et al., Astrophys. J. Lett., 676, L147-L150, 2008.. View full-size photo here.
Outflowing Plasma is Distinct
Outflows at the edges of active regions have low density and radience, which are opposite to similar temperature plasma in the active region.
Del Zanna, Astron. & Astrophys., 481, L49-L52, 2008.. View full-size photo here.
Outflow Driver 1: Magnetic Reconnection
Reconnection at the edges of active regions will produce plamsa jets and chromospheric evaporation, which are both types of outflows.
Baker et al., Astrophys. J., submitted, 2009.. View full-size photo here.
Outflow Driver 2: Active Region Expansion
Expanding active regions can compress neighbouring field, generating forces in the latter that can accelerate plasma upwards as outflows.
Murray et al., Solar Physics, submitted, 2009.. View full-size photo here.
Outflow Driver 3: Coronal Circulation
Outflows may rise along funnels of open magnetic field and sink back to the solar surface along the closed loops of the active regions.
Marsch, Hui, Sun et al., Astrophys. J., 685, 1262-1269, 2008.. View full-size photo here.