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U.S. Department of Energy
Office of Scientific and Technical Information

Observations of coronal mass ejections near the sun

Technical Report ·
OSTI ID:5726909

The appearance and properties of coronal mass ejections (CMEs) near the sun provide clues for their subsequent development in interplanetary space. Observational results are now available for which most, but not all, of a solar cycle. The statistics concerning angular sizes, latitudes, and occurrence rates were compiled, but significant differences between the Skylab/SMM and SOlwind results remain. The structure of classic loop-like CMEs consists of three parts: the bright loop, a dark void, and a bright core, which correspond to coronal loop, prominence cavity, and prominence, respectively. In a few instances the late stages of CMEs have been interpreted as disconnection events with a pinching off of the magnetic field lines and the formation of a closed structure which moves into the interplanetary. Several lines of evidence now show that CMEs have a significant three-dimensional structure rather than something close to a planar shape. While the sources of cool material in CMEs are readily identified with the erupting prominences, the solar sources of hot material observed in the driver gas to interplanetary shocks are not so obvious. The leading edges of CMEs are frequently preceded by waves or shocks which produce deflections in coronal streamers. The relationship between CMEs and type II burst shocks is unclear, however, since some fast CMEs do not result in type II bursts and some type II bursts are not associated with CMEs.

Research Organization:
Emmanuel Coll., Boston, MA (USA). Physics Research Div.
OSTI ID:
5726909
Report Number(s):
AD-A-207956/4/XAB; SCIENTIFIC-3
Country of Publication:
United States
Language:
English