3D CORONAL OBSERVATIONS WITH THE SOLAR CYCLE

摘要

The number of observed aurorae and variable disturbances in the Earth magnetosphere is correlated with the 11 years solar cycle. These phenomena result from 3D solar magnetic field variations and could have many consequences such as loss of satellites control, uncertainties in plane positions, high level of irradiance received by astronauts with high particles, etc... Recent progress in 3D visualization and reconstruction (with stereoscopy and tomography techniques) made it possible to follow the evolution of coronal plasma structures frozen in by the magnetic field. Loops geometries - including their twists measurements -, arcade loops structures or filament shapes, are determined by 3D techniques with SOHO, using the solar rotation. A 3D analysis of the flare formation on April 4th, 1997 shows an emerging flux near a sigmoid loop with magnetic fields reconnection. Other observations emphasize the role of the helicity (observed for example as a twist, in many structures) in filament eruptions and CME formations. Detwisting processes from EIT images to coronagraphic data show ejections of material into the interplanetary space.