SINGULARITIES IN WAVY STRINGS

Extremal six-dimensional black string solutions with some non-trivial momentum distribution along the wave are considered. These solutions w ere recently shown to contain a singularity at the would-be position o f the event horizon. In the black string geometry, all curvature invar iants are finite at the horizon. It is shown that if the effects of in falling matter are included, there are curvature invariants which dive rge there. This implies that quantum corrections will be important at the would-be horizon. The effect of this singularity on test strings i s also considered, and it is shown that it leads to a divergent excita tion of the string. The quantum corrections will therefore be importan t for test objects.