  The generation of higher harmonics of the magnetoplasmon frequency which has
recently been reported in strongly coupled two-dimensional Yukawa systems is
investigated in detail and, in addition, extended to two-dimensional Coulomb
systems. We observe higher harmonics over a much larger frequency range than
before and compare the theoretical prediction with the simulations. The
influence of the coupling, structure, and thermal energy on the excitation of
these modes is examined in detail. We also report on the effect of friction on
the mode spectra to make predictions about the experimental observability of
this new effect.
