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Session 101 - SOHO.
Invited session, Friday, January 09
International Ballroom Center,
The Large Angle Spectroscopic Coronagraph (LASCO) experiment on the SOHO satellite images continuously the solar corona from the surface of the Sun to 32 solar radii. Motion pictures show the dynamics of the corona from the surface of the Sun into the interplanetary medium. Three different electrodynamic processes seem to be responsible for the dynamic state of the corona: Newly emerging magnetic flux from the solar convection zone, conversion of magnetic into mechanical energy by reconnection, and an electrodynamic circuit which couples these processes on a global scale. In the lower corona newly emerging magnetic flux drives the expansion of loop structures into the upper corona, where they react with the global quadrupole magnetic field by reconnection, depositing mass and energy into the global current sheet. Excess energy is released as coronal mass ejections (CMEs). A string of CMEs forms the low latitude, slow speed solar wind, which is accelerated in the equatorial current sheet.
The high speed solar wind is accelerated in open, straight magnetic fields at higher latitudes.
Reconnections of local magnetic fields can drive supersonic shock waves, which are the forefront of large, high speed CMEs. Global energy release inside the equatorial current sheet cause global toroidal CMEs all around the Sun. They require a global energy coupling mechanism in the corona. Large local coronal energy releases-CMEs, flares-seem to change the global structure of the corona.
