Astron. Astrophys. 361, 303-320 (2000)
Appendix A: the fastest growing mode
The most unstable wavenumber, ,
can be found from Eq. (49) by applying the necessary and
sufficient conditions for :
![[EQUATION]](img490.gif)
The first condition yields
![[EQUATION]](img491.gif)
and therefore
![[EQUATION]](img492.gif)
Condition (ii) requires
![[EQUATION]](img493.gif)
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
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