  We studied equally charged particles, suspended in a complex plasma, which
move in a plane and interact with a screened Coulomb potential (Yukawa type)
and with an additional external confining parabolic potential in one direction,
that makes the system quasi-one-dimensional (Q1D). The normal modes of the
system are studied in the presence of dissipation. We also investigated how a
perpendicular magnetic field couples the phonon modes with each other. Two
different ways of exciting the normal modes are discussed: 1) a uniform
excitation of the Q1D lattice, and 2) a local forced excitation of the system
in which one particle is driven by e.g. a laser. Our results are in very good
agreement with recent experimental findings on a finite single chain system
(Phys. Rev. Lett. {\bf 91}, 255003 (2003)). Predictions are made for the normal
modes of multi-chain structures in the presence of damping.
