Closed and open magnetic fields in stellar atmospheres Effects on mass loss from cool giant stars

The author proposes that the onset of rapid mass loss among cool giants, and the absence of hot coronal material from their atmospheres, is associated with a transition in the large-scale magnetic topology of the atmosphere from closed to open. According to this view, field loops in the atmospheres of giants of spectral class K and later cannot find equilibrium, but are in a state of dynamical evolution throughout their lifetime in the atmosphere.