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CHAPTER 14. RELATED CONCEPTS
these perturbations is plotted in part (b) as a function of the modulation wave number
k. For k = 0 the gain is zero because the structure is stable in the one-dimensional case.
The exponential growth results mainly in a snake-like instability of the entire front, as
shown in part (c). The polarization front eventually decays, resulting in a complicated
moving structure such as shown in part (d).
The filamentary structures seen in Figure 14.23(d) possess many interesting prop-
erties, the most important being that they can be stable in two transverse dimensions
[ 113]. It can be interpreted as a stable, ...