Polar plumes in coronal expansion

Several major structures in the solar corona might share similar formation mechanisms. A case in point is the magnetic field reconnection effect which could provide the basic driving force behind the production of spicules and polar plumes. A more realistic consideration of the three-dimensional reconnection process leads to the idea that the solar spicules and coronal plumes should be characterized by twisted flux loops carrying strong current flows. This provides the linkage between the solar corona to the large-scale heliosphere. Even though the polar plumes do not supply the majority of the solar wind, they could play a key role in guiding the low-frequency Alfven waves to large coronal heights. The high level of perpendicular temperatures of the soalr wind protons and minor ions-as probably observed by SOHO/UVCS-might be maintained in this way.