  I study a relativistic open string coupling through its endpoints to a plane
wave with arbitrary temporal profile. The string's transverse oscillations
respond linearly to the external field. This makes it possible to solve the
classical equations, and to calculate the quantum-mechanical S-matrix in closed
form. I analyze the dynamics of the string as the characteristic frequency and
duration of the pulse are continuously varied. I derive, in particular, the
multipole expansion in the adiabatic limit of very long wavelengths, and
discuss also more violent phenomena such as shock waves, cusps and null brane
intersections. Apart from their relevance to the study of time-dependence in
superstring theory, these results could have other applications, such as the
teleportation of gravitational wave bursts by cosmic strings.
