  Global monochromatic solutions of the scalar wave equation are obtained in
flat wormholes of dimensions 2+1 and 3+1. The solutions are in the form of
infinite series involving cylindirical and spherical wave functions and they
are elucidated by the multiple scattering method. Explicit solutions for some
limiting cases are illustrated as well. The results presented in this work
constitute instances of solutions of the scalar wave equation in a spacetime
admitting closed timelike curves.
