On magnetohydrodynamic thermal instabilities in magnetic flux tubes

The authors discuss the stability of current-driven filamentary modes in magnetic flux tubes embedded in a plane-parallel atmosphere in LTE and in hydrostatic equilibrium. Within the tube only energy transport by radiation is considered. The dominant contribution to the opacity is due to H- ions and H atoms (in the Paschen continuum). The authors delimit a region in the parameter space of the equilibrium configuration in which the instability is effective, and they discuss the relevance of this process for the formation of structured coronae in late-type stars and accretion disks.