Solar eruptive phenomena

Abstract

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.

Incompressible magnetohydrodynamic modes in the thin magnetically twisted flux tube

“…Suydam 1959;Bateman 1978;Galeev & Sudan 1989;Cheremnykh 1989;Burdo et al 1994) plasmas. This geometry is also a useful approximation in solving fundamental problems of plasma physics (see for example Trubnikov 1966;Filippov 2007;Cheremnykh et al 1994;Zagorodny & Cheremnykh 2014), to name but a few. In spite of many previous theoretical studies of wave propagation in solar magnetic flux tubes many questions still remain open.…”

“…There are at least two contradictory opinions on how the radial dependence of the equilibrium azimuthal component of the magnetic field outside of the flux tube should be modelled. Filippov (2007); Vršnak (2008) assume that external magnetic field decreases with distance from the tube boundary inversely proportional to the radius, that is, as a function of 1/r. This approximation was previously used by, for example, Erdélyi & Fedun (2006); Ruderman (2015); Giagkiozis et al (2015).…”