Nonlinear resonances of particles in a dusty plasma sheath - art. no. 066403

Vertical oscillations microparticles trapped in the sheath of a capacitive rf discharge have been excited showing a strongly nonlinear resonance. The nonlinear oscillations are analyzed in terms of an anharmonic fourth-order potential energy curve. It is demonstrated that the observed nonlinearities can be related to a position dependent charge of the microspheres, whereas the electric field is found to be as nearly linearly increasing. The exper imental results on the position dependent charging and electric field struc ture are compared to a numerical model.