## Appendix A: coefficients of the stability equationThe coefficients of the stability equation (25) are determined by the equilibrium model (subscript "0") and thus are functions of the unperturbed arclength or alternatively of the unperturbed horizontal distance . In the latter case they read in detail: with the path of the flux tube , , the cross-section , the sound speed , the Alfvén speed and the tube speed , given by . The subscript `e' corresponds to the external plasma. denotes the density scale height, given by . Note that is a constant. © European Southern Observatory (ESO) 1999 Online publication: March 1, 1999 |