## Appendix A: the fastest growing modeThe most unstable wavenumber, , can be found from Eq. (49) by applying the necessary and sufficient conditions for : and therefore where and are shorthand for the expressions in square and curly brackets in Eq. (A.1). In Eq. (A.3) the term in curly brackets vanishes for and the term in square brackets is which is real and positive for . The term in round brackets is always negative and hence . © European Southern Observatory (ESO) 2000 Online publication: January 29, 2001 |