The most probable initial magnetic configuration of a CME is a flux rope
consisting of twisted field lines which fill the whole volume of a dark coronal
cavity. The flux ropes can be in stable equilibrium in the coronal magnetic
field for weeks and even months, but suddenly they loose their stability and
erupt with high speed. Their transition to the unstable phase depends on the
parameters of the flux rope (i.e., total electric current, twist, mass loading
etc.), as well as on the properties of the ambient coronal magnetic field. One
of the major governing factors is the vertical gradient of the coronal magnetic
field which is estimated as decay index (n). Cold dense prominence material can
be collected in the lower parts of the helical flux tubes. Filaments are
therefore good tracers of the flux ropes in the corona, which become visible
long before the beginning of the eruption. The perspectives of the filament
eruptions and following CMEs can be estimated by the comparison of observed
filament heights with calculated decay index distributions. The present paper
reviews the formation of magnetic flux ropes, their stable and unstable phases,
eruption conditions, and also discusses their physical implications in the
solar corona.Comment: 27 pages, 14 figures; to appear in Journal of Astrophysics &
Astronomy (Special Issue; Eds: V. Fedun, A.K. Srivastava, R. Erdelyi, J.C.
Pandey
At the beginning of the 1990s, it was found out that the strongest disturbances of space weather were associated with huge ejections of matter from the solar corona, which took the form of the magnetic clouds when moved from the Sun. It is the collisions of the magnetic clouds with the Earth's magnetosphere that lead to strong, sometimes to catastrophic, changes in space weather. The onset of a coronal mass ejection (CME) is sudden and no reliable forerunners of ɋɆȿs have been found till now. The problem of CME prediction is less developed than the problem of solar flare prediction. The most probable initial magnetic configuration of a CME is a flux rope consisting of twisted field lines which fill the whole volume of a dark coronal cavity. Cold dense prominence material can be collected in the lower parts of the helical flux tubes. Filaments are then the best tracers of the flux ropes in the corona, visible long before the beginning of the eruption.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.