Modulation of a TM mode surface wave on a free boundary between plasma and vacuum

A nonlinear Schroedinger equation is derived by perturbation analysis for a transverse magnetic (TM) mode surface wave propagating on a plasma bounded by free space, taking into account all the nonlinearities including the nonlinear boundary conditions and the kinematics of the rippling boundary, by formulating the boundary conditions in terms of the currents and the surface charges. The nonlinear frequency shift is also obtained for the case of a fixed boundary and is compared with the case of moving boundary. We find that bright solitons can be obtained over the almost entire range of values of the dielectric constant, i.e. εd < -1, for a moving boundary while the fixed boundary gives bright solitons only for the dielectric constant smaller than -3. (author)