PARABOLIC FOCAL CONIC - NEW SMECTIC A DEFECT

The special case of a focal conic defect in which the line discontinuities form a pair of confocal parabolas (a parabolic focal conic) has been observed in smectic A cyanobenzylidene octyoxyaniline. The geometry of these defects has been studied and used to determine their interactions with bounding surfaces and with each other. The polygonal texture obtained by dilation of smectic A and cholesteric plane textures is shown to be an array of parabolic focal cone defects. The generation and structure of such arrays is discussed.